1 An Artificial Solid Electrolyte Interphase Layer for Lithium Metal

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An Artificial Solid Electrolyte Interphase Layer for Lithium Metal Anode in High Energy Lithium Secondary Pouch Cells Wen Liu, Rui Guo, Bin-Xin Zhan, Bin Shi, Yong Li, Haijuan Pei, Yong Wang, Wei Shi, Zhengwen Fu, and Jingying Xie ACS Appl. Energy Mater., Just Accepted Manuscript • DOI: 10.1021/acsaem.8b00132 • Publication Date (Web): 23 Mar 2018 Downloaded from http://pubs.acs.org on March 24, 2018

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ACS Applied Energy Materials

An Artificial Solid Electrolyte Interphase Layer for Lithium Metal Anode in High Energy Lithium Secondary Pouch Cells Wen Liua, Rui Guoa, Binxin Zhanb, Bin Shia, Yong Lia, Haijuan Peia, Yong Wanga, Wei Shia, Zhengwen Fuc and Jingying Xiea*

a

Space Power Technology State Key Laboratory, Shanghai Institute of Space Power-

Sources, Shanghai 200245, P. R. China. b

c

Tianqi Lithium Chengdu Ltd., Chengdu 610041, P. R. China. Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials,

Department of Chemistry, Fudan University, Shanghai 200433, P. R. China. *Corresponding author: Shanghai Institute of Space Power-Sources, 2965#, Dongchuan Road, Shanghai, 200245, P. R. China. Tel.: +86-21-24187673, Fax: +8621-24188008. E-mail address: [email protected]

Abstract Lithium secondary batteries have attracted considerable attention due to their great potential to achieve ultrahigh energy density for future use. However, Li metal anode suffers dendrite formation during repeated stripping/plating, hindering its practical realization. Herein, for the first time, an artificial solid electrolyte interphase layer, lithium phosphorus oxynitride (LiPON), is introduced for lithium anode and the viable application in high energy lithium secondary pouch cell is probed. LiPON is stable with lithium and in the air, which can protect the lithium from the side reaction with H2O and O2 effectively. In low-energy batteries, LiPON layer can enhance the efficiency of lithium deposition/dissolution and prolong the lifespan of the batteries. Further on, the discharge capacities of the lithium secondary cells with an energy

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density over 350 Wh kg−1 deploying LiPON coated Li anodes drop fast and the batteries prone severe polarization leading to the termination of life. Nonuniform current density resulting from the cracks caused by the large mass of lithium stripping/plating is ascribed to the decisive factor shortening the life of batteries. Generally speaking, more and further exploration should be focused on the modification of large-area lithium anode to accomplish high-energy-density lithium batteries for practical applications.

Keywords: lithium metal anode, solid electrolyte interphase layer, LiPON, high energy density, pouch cell


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1 Introduction Lithium secondary batteries deploying metal lithium as anode were proposed as one high-energy battery system, which were initialized in 1962.[1] Unfortunately, the commercial use of lithium secondary batteries was halted because of dendrite formation on the surface of the lithium electrode, depletion of the electrolyte and notorious safety issue resulting from the activeness of dendrite.[1-2] Recently, different innovative approaches have developed to solve these difficulties, so that lithium secondary batteries with high energy density and long cycle life will be a favorable option for different applications.[3-10] These techniques can be classified as the following:[11] in situ formation of stable solid electrolyte interphase (SEI) film (organic solvents, Li salts, functional additives); ex situ-formed surface coating; mechanical blocking (polymer electrolytes, polymeric single ion conductors, inorganic-organic hybrid electrolytes, inorganic solid state Li-ion conductors); selfhealing electrostatic shield mechanism and other factors (pressure, substrate smoothness, substrate area). However, there were rare strategies for large area lithium anode in large capacity full cells (such as pouch cells) with high energy density and areal capacity.[12-15] For example, Li anodes with hexagonal boron nitride (h-BN) protection were cycled at different areal capacity of 1.0, 3.0 and 5.0 mAh cm−2 in 2032 coin cell.[12] Li metal foil with ultrathin Al2O3 layers (∼2 nm) using atomic layer deposition (ALD) can be cycled at 0.25 mAh cm−2 for 1259 cycles before failure occurs in Li symmetric cells.[13] Coin cells CR2032 were used to estimate the electrochemical stability and lifespan of Li anode employing different Cu current collectors with a capacity density of 1 mAh cm−2.[14] In Li-S pouch cells, Li metal powdering and the induced polarization are more responsible for pouch cell failure rather than Li polysulfide shuttle issue,[16] indicating that many unexpected issues



would appear when developing rechargeable lithium batteries with high capacity, high energy density, high safety and long lifespan. Much attention should be paid on transplant coin cell strategy to a large capacity cell. On the other hand, lithium batteries also occur cell failure because of the insufficiency of electrolyte.[2, 13, 17-19] Lithium solid electrolytes owe such properties: suitable mechanical strength,[20-21] suitable ionic transport properties,[22-23] wide electrochemical stability window,[24-25] and intrinsic safety,[26] enabling these solid electrolytes as one protecting layer for lithium anode.[27-29] Lithium phosphorus oxynitride (LiPON), an amorphous solid state electrolyte for all-solid-state thin film lithium batteries,[30-35] has been introduced as an artificial SEI on LiNi0.5Mn1.5O4 high voltage cathode to suppress the decomposition of electrolyte and LixMn2-yO4 thin film cathode to stabilize the cathode interface,[36-37] which provides paths for lithium ions conduction and maintains mechanical integrity during cycling. Also, LiPON coating improves the rate capability and the thermal stability of the charged LiCoO2 cathode, which could be explained by that LiPON film appears to suppress impedance growth during cycling and inhibits side-reactions between delithiated LiCoO2 and the electrolyte.[38] Furthermore, LiPON is chemically stable with metal Li,[39] which was potential to use as a protective layer for lithium anode for protecting the electrode surface from electrolytic decomposition and enhancing the cycle life in liquid electrolyte.[40-41] But the study of the feasibility of large-area protected Li anode in pouch cells is scarce. In this work, we report for the first time, to our knowledge, that the possible use of LiPON as a protective layer in high-energy and large-capacity lithium secondary pouch cells using different two types of liquid electrolytes (ethers and carbonates) and three kinds of cathodes was investigated systematically.


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2 Experimental Sections 2.1 Preparation of LiPON and LiPON-coated electrode The LiPON layer was deposited on Cu or Li electrodes by Radio Freqency (RF) reactive sputtering of a Li3PO4 target in nitrogen plasma in the dry room with dew point lower -40 °C to prepare LiPON coated Cu or LiPON coated Li electrodes,[41-42] denoted as LiPON@Cu or LiPON@Li, respectively. 2.2 Preparation of coin cells The LiPON@Cu or bare Cu with a diameter of 14 mm were used as working electrodes for lithium deposition. One sheet of high-purity lithium foil (99.9%) was used as the counter and reference electrodes. 1.2 M LiPF6 non-aqueous solution in 3:7 (v/v) ethylene carbonate (EC) and dimethyl carbonate (DMC) solvent (Fosai New Material

Co.

Ltd.)

was

used

as

the

electrolyte.

Celgard

2325

(polypropylene/polyethylene/polypropylene, PP/PE/PP) membrane was used as separator. The 2016-type coin cells were assembled in an argon-filled glovebox with both contents of O2 and H2O below 0.1 ppm. 2.3 Preparation of pouch cells The pouch cells were assembled in a dry room with dew point lower -40 °C. The cathodes were composed of active material (LiCoO2 (dubbed as LCO), LiNi0.8Co0.15Al0.05O2 (dubbed as NCA) or S), electrical conductor (Super P), and binder (polyvinylidenefluoride (PVDF)) on aluminum foil. The detailed parameters (cell capacity, capacity density, cathode loading, active material percent of cathode, cathode area, the capacity ratio of anode and cathode (N/P) and the mass ratio of electrolyte and active material (E/P)) and classifications of the pouch cells in this work were tabulated in Table S1. The capacity density of cathodes were 2.24, 12.03 and 9.45 mAh cm−2 for LCO, NCA and S cathodes, respectively. The different 5 ACS Paragon Plus Environment


chemistries of cathode materials were seclected for matching different cathode loading, capacity density and electrolyte system. NCA cathode was chosen for its high specific capacity and high cathode loading, which is beneficial to obtain a higher energy density (over 350 Wh kg−1). The width and length of Li anodes (Cu electrodes in anode-free cells) were 0.1 mm larger, i.e. 8.1×8.1 cm2, than those of cathodes. A layer-by-layer process has been used to alternate the cathodes and anodes with Celgard 2325 membrane acting as the separator in pouch cells. The cells were assembled and sealed in a laminated aluminum film bag. 1.2 M LiPF6 non-aqueous solution in 3:7 (v/v) ethylene carbonate (EC) and dimethyl carbonate (DMC) solvent (Fosai New Material Co. Ltd.) was used as the electrolyte for LCO and NCA cells, and 1 M LiTFSI non-aqueous solution in 1:1 (v/v) 1,2-dimethoxyethane (DME) and 1,3-dioxolane (DOL) (Fosai New Material Co. Ltd.) was used as the electrolyte for S cells. In the anode-free three-electrode pouch cells, LiPON@Cu or bare Cu were used as counter electrode for lithium deposition, Cu wire with a diameter of 22 µm deposited with a little lithium was used as reference electrode. The deposition of lithium was carried out before normal cycling of the cell. 2.4 Structural Characterization Scanning electron microscope (SEM) images and Energy dispersive X-ray spectroscope (EDX) were captured using a field emission scanning electron microscope (FE-SEM, Hitachi S-4800) operated at an acceleration voltage of 10 kV. X-ray photoelectric spectroscopy (XPS) analysis was carried out on a PHI 5000C system (Perkin Elmer) with a monochromatic Al Kα X-ray source. The cion cells and pouch cells were all disassembled in an argon-filled glovebox (H2O < 0.1 ppm, O2 < 0.1 ppm) for further characterizations. 2.5 Electrochemical Characterization 6 ACS Paragon Plus Environment

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Galvanostatic charge-discharge measurements were carried out at room temperature with a Land CT 2001A battery test system. In coin cells, various areal capacity of Li was deposited on working electrode at various current densities and Li was stripped until the potential up to 0.5 V (vs. Li+/Li). In pouch cells, the current densities were calculated based on the capacity of the pouch cells. The 1 C-rate is defined as the pouch cell fully discharging in 1 h. All cells cycled at the rate of 0.1 C. In anode-free three-electrode pouch cell, 75 µAh lithium was deposited on Cu wire reference electrode at the current of 5 µA, using Cu wire as temporary working electrode and LCO as counter electrode. Electrochemical impedance spectroscopies (EIS) of the cells were taken on Princeton Applied Research electrochemical workstation in a frequency range of 1.0 MHz to 0.1 Hz. 3 Results and discussion Figure S1(a) shows the SEM of pristine Li electrode, revealing a rough and uneven surface. As clearly observed in Figure 1(a), a layer of 2 µm was deposited on the surface of lithium electrode, which was compact (Figure S1(b)) and composed of spherical particles, seen in Figure 1(b) and Figure S1(c). EDX maps obtained of the layer, depicted in Figure S1(d-f), show that oxygen, phosphorus and nitrogen are uniformly distributed on the surface of Li metal, indicating that LiPON has a uniform distribution on the surface of the Li metal (element lithium cannot be detected via EDX mapping). The atom proportions of elements C, O, Li, N, and P detected by XPS were 72.06, 17.05, 9.13, 0.34, 1.42%, respectively (see Figure S1(g)). When preparing the SEM samples using blade, there were many cracks on the LiPON layer, implying that shearing force would break LiPON and LiPON was fragile (Figure S1(h)).



Figure 1. SEM images of LiPON layer deposited on lithium electrode: (a) side-view image; (b) top-view image. A lithium metal with partly LiPON-coating was placed during atmospheric exposure at room temperature for 10 days (Figure S2). The red square shows the size of the LiPON layer, under which the surface of lithium metal was bright and intact. While the other area of lithium was black and covered with white particles, resulting from the reaction of O2, H2O, even N2 in the air. Considering the blocking off the air and the stability with lithium,[39] in some scenarios, we believe that LiPON will be an artificial “SEI” film for lithium metal anodes for realizing long time and stable cycling. First, asymmetric Li/Cu and Li/LiPON@Cu coin cells were used to characterize the protecting effect of LiPON layer. Figure S3 shows the Columbic efficiency (CE) versus cycle number for both Li/Cu and Li/LiPON@Cu cells at various current density and capacity density. It is apparent that the LiPON@Cu electrode emerges higher CE at all test conditions, indicating a better cycling performance and effective protection of lithium during its stripping and plating. Furthmore, the morphology of LiPON@Cu electrodes after Li deposition were displayed as Figure S4. Unconspicuous changes were found, implying good stability of LiPON layer.


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To furthur confirm the hypothesis of protecting of LiPON layer for Li anode in pouch cells, an anode-free three-electrode pouch cell was fabricated to enable synchronized observation of voltage trace of cathode, anode and the full cell during galvanostatic cycling. Figure 2 presents the schematic diagram and the electrochemical properties of anode-free three-electrode pouch cell with LiPON@Cu as counter electrode, Cu wire as reference electrode and LCO as cathode. Meanwhile, the electrochemical performances of LCO/Cu cell were provided for comparison. As depicted in Figure 2(b), the difference of voltage between full cell and cathode was negligibly small, revealing the extremely low stripping/plating voltage of Li anode. Furthermore, the voltage of LiPON@Cu electrode exhibited typical lithium deposition/dissolution curves, revealing that LiPON layer had no side effects on the electrochemical properties in this pouch cell. The first two voltage profiles, seen in Figure 2(c), show that no subtle difference of polarization was observed between Cu/LCO and LiPON@Cu/LCO pouch cell. However, the discharge capacity of Cu/LCO cell fades much severely than that of LiPON@Cu/LCO cell (Figure 2(d)), exhibiting a worse cycle performance. These results imply that LiPON can act as a protective layer for lithium anode and enhance the efficiency of lithium deposition/dissolution on bare Cu electrode in despite of the laggardly fading of capacity.



Figure 2. (a) Schematic of the anode-free battery with LiPON@Cu as counter electrode; (b) the potential curves of cathode, anode and full cell in a three-electrode pouch cell, deploying copper wire deposited with lithium as reference electrode; (c) the first two discharge/charge curves and (d) cycle performances of LiPON@Cu/LCO and Cu/LCO pouch cell. In order to probe the effect of LiPON in full cells, pouch cells (cell 3 and 4 in Table S1 with N/P of about 30) composed of one piece of LCO cathode and one piece of LiPON@Li or Li anode were fabricated. To understand the evolution of interface characteristics, the EIS of both Li anodes after standing different times before electrochemical cycling were measured and are presented in Figure 3(a). It is apparent that the impedance spectra are composed of a compressed semicircle in the highfrequency region and an inclined line in the low-frequency region for both cells, corresponding to the interfacial charge transfer process and Warburg diffusion process, respectively. Before cycles, the ohmic resistance (Rs) of solution and interfacial charge-transfer resistance (Rct) of bare lithium anode are lower than those of the LiPON@Li anode, which was accounted for the lower conductivity of LiPON layer 10 ACS Paragon Plus Environment

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on the lithium anode.[30, 32] On the other hand, Rs and Rct remain almost identical after short standing times (16 and 46 h) for Li/LCO and LiPON@Li/LCO cell, respectively, indicating that stable interfaces were formed on both bare Li and LiPON@Li anodes in conventional carbonate based electrolyte. Furthermore, galvanostatic discharge/charge measurements were carried out to investigate the polarization and lifespan of the cells. To ensure a fair comparison, the capacities were normalized as the first discharge capacity. As depicted in Figure S5, there was a subtle difference between the polarization of two cells, evidencing negligible effects on the polarization of LiPON in Li/LCO cells. Cycle life and Columbic efficiency are critical index to evaluate the stability of Li in Li secondary batteries. At the beginning of cycles, LiPON@Li/LCO cell revealed a higher discharge capacity (141.2 mAh in the 1st cycle) and much enhanced cyclability (80.67% of the initial discharge capacity after 100 cycles) compared to those of bare Li/LCO cell (98.2 mAh in the 1st cycle, 59.80% of the initial discharge capacity after 31 cycles), see Figure 3(b). This may be ascribed to much more formation of SEI film during the first several cycles in bare Li/LCO cell.[43] And, the capacity of bare Li/LCO cell degraded severely until the termination of life (31 cycles), accompanying the fading Columbic efficiency. While the capacity of LiPON@Li/LCO cell stayed stable and degraded gradually after 100 cycles with an average Columbic efficiency of 98.06%, indicating that LiPON@Li anode achieved dramatically improved cycling stability and cycle lifespan when the cell employed LCO as cathode in carbonate based electrolyte.



Figure 3. The comparison of the electrochemical performances of bare Li/LCO and LiPON@Li/LCO cell. (a) Evolution of impedance spectra of the cell after standing different times before cycling; (b) capacity of cells and efficiencies as a function of cycle number at 0.1 C. In view of these intriguing results, two types of high-energy-density pouch cells were fabricated to prove the emergence of viable high energy cells: (1) Type 2 in Table S1, one composed of seven pieces of NCA cathodes and eight pieces of LiPON@Li or Li anodes with the energy density of about 400 Wh kg−1; (2) Type 3 in Table S1, one composed of two pieces of S cathodes and three pieces of LiPON@Li or Li anodes with the energy density of about 350 Wh kg−1. As depicted in Figure 4, it showed the comparison of cycling stability in Li/NCA cells and Li/S cells with and without LiPON coating layer. It is disappointed that Li cells with LiPON@Li anodes exhibited even worse cycling stability than those with bare Li anodes, in stark contrast to the results found in Figure 2 and 3. The discharge capacities of Li cells with LiPON layer fades severely, especially in Li/S cells, accompanying with the increasing polarization (Figure S6).


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Figure 4. The discharge capacities as a function of cycle number of Li batteries measured at a rate of 0.1 C: (a) LiPON@Li/NCA and Li/NCA cell; (b) LiPON@Li/S and Li/S cell. We made the hypothesis that the high-energy-dendity cell-design and the fragile characteristic of LiPON may be the two key reasons resulting in the poor cyclic stability in lithium metal batteries with LiPON layer. In Cell 5-8 with high energy density (lower N/P and E/P), a large mass of lithium (∼30 µm cm−2 Li for 6.015 mAh cm−2 (NCA cells), ∼23 µm cm−2 Li for 4.725 mAh cm−2 (S cells), single side) would be deposited and dissolved during each cycle, leading to a superb change of thickness and volume of lithium anodes, which would result in enormous stress underneath the nature SEI or artificial SEI (LiPON). However, LiPON layer was not smart, adaptive or soft enough to tolerate the volumetric or thickness change of Li metal anode during cycles, as a result of the formation of cracks (just as Figure S1(h), cracks were resulted from the shearing force when preparing the sample). The cracks would induce the nonuniform current density on the LiPON@Li anode, evidencing that the lithium dendrite would be easily formed between the cracks.[6, 42] Furthermore, lithium dendrite would consume the electrolyte (the mass ratio of electrolyte to cathode active material (E/P) in pouch cell was lower than 0.46 g g−1 (Li/NCA cell, Type 2) and 2.50 g g−1 (Li/S cell, Type 3) to achieve ultrahigh energy density), as well as the active 13 ACS Paragon Plus Environment


lithium of Li anode.[43] Definitely, the Li metal anode becomes more problematic in cells with higher energy density and cathode capacity density. After cycling to the termination of life, the pouch cells were disassembled in an argon-filled glovebox with O2 and H2O contents all below 0.1 ppm to observe the optical images of the LiPON@Li anodes. Figure S7(a) shows the morphology of LiPON@Li anodes after cycles, the fresh LiPON@Li anodes included for comparison (Figure S7(b)). The bright and intact surface changed to a gray, powdery and wrinkled one, in line with the issue in Li/S pouch cells after cycles.[16] Considering the high reactivity and flammability of powdery lithium (being rooted in the high surface area), only optical images of the LiPON@Li anodes were taken. The wrinkles and cracks on LiPON@Li were assigned to the active area for dendrite formation and reaction area with electrolyte. Moreover, the gray powdery lithium would be easily isolated from Li anode, forming “dead Li”, which was electrochemically inactive. On the other hand, the electrolyte of the pouch cells was dry up and the separator was not saturated with electrolyte, further validating the formation of lithium dendrite and the consumption of the electrolyte, accelerating the cell life end. All evidences above agree with the hypothesis of unsmart LiPON to tolerate the volumetric or thickness change during cycles in lithium batteries with high energy density, which leads to a poor lifespan. At the end, we like to emphasize that the possible effect of cell design with ultrahigh energy density (larger volume/thickness change of Li anodes, lower N/P, lower E/P) was ascribed to the accelerated termination of the cell life, while the cycling performance of cells with low energy density (lower volume/thickness change of Li anodes, higher N/P, higher E/P) deploying LiPON@Li anode were largely improved compared to bare Li anode. The evolution of LiPON@Li anodes in pouch cells with low energy density and ultrahigh energy density are schemed in Figure 5,


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respectively. Inspired by this work, we make the hypothesis that a smart, adaptive, soft enough and stable protective SEI for lithium anode to tolerate the large volumetric or thickness change during cycles is indispensable to obtain a high energy lithium secondary battery for future commercial uses.

Figure 5. Proposed schematic illustration of LiPON@Li anodes in pouch cells with (a) low energy density and (b) ultrahigh energy density after cycles. 4 Conclusions Herein we have demonstrated that an artificial LiPON layer with a thickness of 2 µm was utilized in lithium pouch cells, which were classified as three types (8 kinds) with different energy densities, N/P, E/P and capacity densities of cathodes. In low capacity batteries (140 mAh), no distinct polarizations were observed in LiPON@Li/LCO

pouch

cell,

which

exhibits

enhanced

efficiency

of

Li

stripping/platting (average of 98.06%) and achieves longevity of cycling of 100 cycles, corresponding to a capacity retention of 80.67%, only about 31 cycles in Li/LCO pouch cell as comparison (59.80% of retention). However, the designs of Li/NCA (∼5 Ah) and Li/S (∼1.2 Ah) cells with ultrahigh energy density (corresponding to a larger volume and thickness changes of Li anode, lower N/P and E/P) were assigned to the key factor that weakens the protecting of LiPON for lithium metal anode, leading to a worse lifespan. Further and detailed studies should be carried out to develop a stable



lithium anode for high-energy-density, large-capacity, safe lithium batteries with an ultralong cycle life and excellent efficiency for commercial applications. Acknowledgements This work was financially supported by the National Natural Science Foundation of China (NSFC21373137). Supporting Information Electronic Supporting Information (ESI) available: The parameters of the pouch cells; SEM of pristine Li electrode, LiPON layer and the corresponding EDX; SEM of the edge of LiPON layer after being cut by blade; optical image of LiPON@ Li during atmospheric exposure at room temperature after 10 days; the Columbic efficiency of Li platting/striping in Li/LiPON@Cu and Li/Cu coin cells; SEM images of LiPON@Cu electrode after Li deposition; first two discharge-charge curves of LiPON@Li/LCO and bare Li/LCO cells; the selective discharge-charge curves of LiPON@Li/NCA, Li/NCA, LiPON@Li/S and Li/S cell; optical images of the LiPON@Li anodes before and after cycles. This information is available free of charge via the Internet at http://pubs.acs.org/. References [1] Wang, D.; Zhang, W.; Zheng, W.; Cui, X.; Rojo, T.; Zhang, Q. Towards HighSafe Lithium Metal Anodes: Suppressing Lithium Dendrites via Tuning Surface Energy. Adv. Sci. 2017, 4, 1600168. [2] Mauger, A.; Armand, M.; Julien, C. M.; Zaghib, K. Challenges and Issues Facing Lithium Metal for Solid-State Rechargeable Batteries. J. Power Sources 2017, 353, 333-342. [3] Huang, S.; Tang, L.; Najafabadi, H. S.; Chen, S.; Ren, Z. A Highly Flexible SemiTubular Carbon Film for Stable Lithium Metal Anodes in High-Performance


Page 16 of 27

Page 17 of 27 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Batteries. Nano Energy 2017, 38, 504-509. [4] Lee, Y. G.; Ryu, S.; Sugimoto, T.; Yu, T.; Chang, W.; Yang, Y.; Jung, C.; Woo, J.; Kang, S. G.; Han, H. N.; Doo, S. G.; Hwang, Y.; Chang, H.; Lee, J. M.; Sun, J. Y. Dendrite-Free Lithium Deposition for Lithium Metal Anodes with Interconnected Microsphere Protection. Chem. Mater. 2017, 29, 5906-5914. [5] Wu, H.; Cao, Y.; Geng, L.; Wang, C. In Situ Formation of Stable Interfacial Coating for High Performance Lithium Metal Anodes. Chem. Mater. 2017, 29, 3572-3579. [6] Li, Q.; Zhu, S.; Lu, Y. 3D Porous Cu Current Collector/Li-Metal Composite Anode for Stable Lithium-Metal Batteries. Adv. Funct. Mater. 2017, 27, 1606422. [7] Zhang, R.; Chen, X. R.; Chen, X.; Cheng, X. B.; Zhang, X. Q.; Yan, C.; Zhang, Q. Lithiophilic Sites in Doped Graphene Guide Uniform Lithium Nucleation for Dendrite-Free Lithium Metal Anodes. Angew. Chem. 2017, 56, 7764-7768. [8] Li, N. W.; Yin, Y. X.; Yang, C. P.; Guo, Y. G. An Artificial Solid Electrolyte Interphase Layer for Stable Lithium Metal Anodes. Adv. Mater. 2016, 28, 18531858. [9] Ryou, M. H.; Lee, Y. M.; Lee, Y.; Winter, M.; Bieker, P. Mechanical Surface Modification of Lithium Metal: Towards Improved Li Metal Anode Performance by Directed Li Plating. Adv. Funct. Mater. 2015, 25, 834-841. [10]

Qian, J.; Henderson, W. A.; Xu, W.; Bhattacharya, P.; Engelhard, M.; Borodin,

O.; Zhang, J. G. High Rate and Stable Cycling of Lithium Metal Anode. Nat. Commun. 2016, 6, 6362. [11]

Xu, W.; Wang, J.; Ding, F.; Chen, X.; Nasybulin, E.; Zhang, Y.; Zhang, J. G.

Lithium Metal Anodes for Rechargeable Batteries. Energy Environ. Sci. 2014, 7, 513-537.



[12]

Yan, K.; Lee, H. W.; Gao, T.; Zheng, G.; Yao, H.; Wang, H.; Lu, Z.; Zhou, Y.;

Liang, Z.; Liu, Z.; Chu, S.; Cui, Y. Ultrathin Two-Dimensional Atomic Crystals as Stable Interfacial Layer for Improvement of Lithium Metal Anode. Nano Lett. 2014, 14, 6016-6022. [13]

Kazyak, E.; Wood, K. N.; Dasgupta, N. P. Improved Cycle Life and Stability

of Lithium Metal Anodes Through Ultrathin Atomic Layer Deposition Surface Treatments. Chem. Mater. 2015, 27, 6457-6462. [14]

Zhang, Z.; Xu, X.; Wang, S.; Peng, Z.; Liu, M.; Zhou, J.; Shen, C.; Wang, D.

Li2O Reinforced Cu Nano-Clusters as Porous Structure for Dendrite-Free and Long-Lifespan Lithium Metal Anode. ACS Appl. Mater. Interfaces 2016, 8, 26801-26808. [15]

Lu, Q.; He, Y. B.; Yu, Q.; Li, B.; Kaneti, Y. V.; Yao, Y.; Kang, F.; Yang, Q.

H. Dendrite-Free, High-Rate, Long-Life Lithium Metal Batteries with a 3D Cross-Linked Network Polymer Electrolyte. Adv. Mater. 2017, 29, 1604460. [16]

Cheng, X. B.; Yan, C.; Huang, J. Q.; Li, P.; Zhu, L.; Zhao, L.; Zhang, Y.; Zhu,

W.; Yang, S. T.; Zhang, Q. The Gap between Long Lifespan Li-S Coin and Pouch Cells: The Importance of Lithium Metal Anode Protection. Energy Storage Mater. 2017, 6, 18-25. [17]

Hagen, M.; Fanz, P.; Tübke, J. Cell Energy Density and Electrolyte/Sulfur

Ratio in Li-S Cells. J. Power Sources 2014, 264, 30-34. [18]

Vaughey, J. T.; Liu, G.; Zhang, J. G. Stabilizing the Surface of Lithium Metal.

MRS Bull. 2014, 39, 429-435. [19]

Cheng, X. B.; Zhang, Q. Dendrite-Free Lithium Metal Anodes: Stable Solid

Electrolyte Interphases for High-Efficiency Batteries. J. Mater. Chem. 2015, A3 7207-7209.


Page 18 of 27

Page 19 of 27 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


[20]

Chen, R.; Qu, W.; Guo, X.; Li, L.; Wu, F. The Pursuit of Solid-State

Electrolytes for Lithium Batteries: From Comprehensive Insight to Emerging Horizons. Mater. Horiz. 2016, 3, 487-516. [21]

Janek, J.; Zeier, W. G. A Solid Future for Battery Development. Nat. Energy

2016, 1, 16141. [22]

Zuo, X.; Liu, X. M.; Cai, F.; Yang, H.; Shen, X. D.; Liu, G. A Novel All-Solid

Electrolyte Based on a Co-polymer of Poly-(methoxy/hexadecal-poly(ethylene glycol) Methacrylate) for Lithium-Ion Cell. J. Mater. Chem. 2012, 22, 2226522271. [23]

Hayashi, A.; Harayama, T.; Mizuno, F.; Tatsumisago, M. Characterization of

Hybrid Electrolytes Prepared from the Li2S-P2S5 Glasses and Alkanediols. Solid State Ionics 2011, 192, 130-133. [24]

Hayashi, A.; Hama, S.; Mizuno, F.; Tadanaga, K.; Minami, T.; Tatsumisago,

M. Characterization of Li2S-P2S5 Glass-Ceramics as a Solid Electrolyte for Lithium Secondary Batteries. Solid State Ionics 2004, 175, 683-686. [25]

Minami, K.; Hayashi, A.; Ujiie, S.; Tatsumisago, M. Electrical and

Electrochemical Properties of Glass-Ceramic Electrolytes in the Systems Li2SP2S5-P2S3 and Li2S-P2S5-P2O5. Solid State Ionics 2011, 192, 122-125. [26]

Manthiram, A.; Yu, X.; Wang, S. Lithium Battery Chemistries Enabled by

Solid-State Electrolytes. Nat. Rev. 2017, 2, 16013. [27]

Zhao, C. Z.; Cheng, X. B.; Zhang, R.; Peng, H. J.; Huang, J. Q.; Ran, R.;

Huang, Z. H.; Wei, F.; Zhang, Q. Li2S5-Based Ternary-Salt Electrolyte for Robust Lithium Metal Anode. Energy Storage Mater. 2016, 3, 77-84. [28]

Zhou, W.; Wang, S.; Li, Y.; Xin, S.; Manthiram, A.; Goodenough, J. B.

Plating a Dendrite-Free Lithium Anode with a Polymer/Ceramic/Polymer



Sandwich Electrolyte. J. Am. Chem. Soc. 2016, 138, 9385-9388. [29]

Leung, K.; Soto, F. A.; Hankins, K.; Balbuena, P. B.; Harrison, K. L. Stability

of Solid Electrolyte Interphase Components on Lithium Metal and Reactive Anode Material Surfaces. J. Phys. Chem. C 2016, 120, 6302-6313. [30]

Nowak, S.; Berkemeier, F.; Schmitz, G. Ultra-Thin LiPON Films-

Fundamental Properties and Application in Solid State Thin Film Model Batteries. J. Power Sources 2015, 275, 144-150. [31]

Dudney, N. J.; Neudecker, B. J. Solid State Thin-Film Lithium Battery

Systems. Curr. Opin. Solid State Mater. Sci. 1999, 4, 479-482. [32]

Li, D.; Ma, Z.; Xu, J.; Li, Y.; Xie, K. High Temperature Property of All-Solid-

State Thin Film Lithium Battery Using LiPON Electrolyte. Mater. Lett. 2014, 134, 237-239. [33]

Santhanagopalan, D.; Qian, D.; McGilvray, T.; Wang, Z.; Wang, F.; Camino,

F.; Graetz, J.; Dudney N.; Meng, Y. S. Interface Limited Lithium Transport in Solid-State Batteries. J. Phys. Chem. Lett. 2014, 5, 298-303. [34]

Schwöbela, A.; Precht, R.; Motzko, M.; Solano, M. A. C.; Calvet, W.;

Hausbrand, R.; Jaegermann, W. Determination of the Valence Band Structure of an Alkali Phosphorusoxynitride Glass: A Synchrotron XPS Study on LiPON. Appl. Surf. Sci. 2014, 321, 55-60. [35]

Guille, É.; Vallverdu, G.; Baraille, I. First-Principle Calculation of Core Level

Binding Energies of LixPOyNz Solid Electrolyte. J. Chem. Phys. 2014, 141, 244703. [36]

Li, J.; Baggetto, L.; Martha, S. K.; Veith, G. M.; Nanda, J.; Liang, C.; Dudney,

N. J. An Artificial Solid Electrolyte Interphase Enables the Use of a LiNi0.5Mn1.5O4 5 V Cathode with Conventional Electrolytes. Adv. Energy Mater.


Page 20 of 27

Page 21 of 27 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


2013, 3, 1275-1278. [37]

Dudney, N. J. Addition of a Thin-Film Inorganic Solid Electrolyte (Lipon) as a

Protective Film in Lithium Batteries with a Liquid Electrolyte. J. Power Sources 2000, 89, 176-179. [38]

Choi, K. H.; Jeon, J. H.; Park, H. K.; Lee, S. M. Electrochemical Performance

and Thermal Stability of LiCoO2 Cathodes Surface-Modified with a Sputtered Thin Film of Lithium Phosphorous Oxynitride. J. Power Source 2010, 195, 83178321. [39]

West, W. C.; Whitacre, J. F.; Lim, J. R. Chemical Stability Enhancement of

Lithium Conducting Solid Electrolyte Plates Using Sputtered LiPON Thin Films. J. Power Sources 2004, 126, 134-138. [40]

Chung, K.; Kim, W. S.; Choi, Y. K. Lithium Phosphorous Oxynitride as a

Passive Layer for Anodes in Lithium Secondary Batteries. J. Electroanal. Chem. 2004, 66, 263-267. [41] Z.

Zhou, B.; Guo, L.; Zhang, Y.; Wang, J.; Ma, L.; Zhang, W. H.; Fu, Z.; Peng, A

High-Performance

Li–O2

Battery

with

a

Strongly

Solvating

Hexamethylphosphoramide Electrolyte and a LiPON-Protected Lithium Anode. Adv. Mater. 2017, 29, 1701568. [42]

Liu, W. Y.; Fu, Z. W.; Qin, Q. Z. A Sequential Thin-Film Deposition

Equipment for In-Situ Fabricating All-Solid-State Thin Film Lithium Batteries. Thin Solid Films 2007, 515, 4045-4048. [43]

Jiao, S.; Zheng, J.; Li, Q.; Li, X.; Engelhard, M. H.; Cao, R.; Zhang, J. G.; Xu,

W. Behavior of Lithium Metal Anodes under Various Capacity Utilization and High Current Density in Lithium Metal Batteries. Joule 2018, 2, 1-15.



Table of Contents


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1 An Artificial Solid Electrolyte Interphase Layer for Lithium Metal

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