Cobalt Nanoparticles Chemically Bonded to Porous Carbon

Jan 8, 2018 - An appropriate amount of NaCl was then mixed with the saturated solution, which was intentionally used for avoiding template dissolution...
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Cobalt nanoparticles chemically bonded to porous carbon nanosheets: A stable high-capacity anode for fast-charging lithium-ion batteries Vinodkumar Etacheri, Chulgi Hong, Jialiang Tang, and Vilas G. Pol ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.7b15915 • Publication Date (Web): 08 Jan 2018 Downloaded from http://pubs.acs.org on January 8, 2018

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ACS Applied Materials & Interfaces

Cobalt nanoparticles chemically bonded to porous carbon nanosheets: A stable high-capacity anode for fast-charging lithiumion batteries Vinodkumar Etacheri a, b, *, Chulgi Nathan Hong a, c, Jialiang Tang a, and Vilas G. Pol a, * a

Davidson School of Chemical Engineering, Purdue University, 480 Stadium Mall Drive West Lafayette, Indiana 47907-2100, United States b

IMDEA Materials Institute, C/ Eric Kandel 2, Getafe, Madrid 28906, Spain c

Battery R&D, LG Chem Ltd., 104-1 Moonji-dong, Yuseong-gu, Daejeon, 305-380, Republic of Korea

KEYWORDS: Lithium ion battery; Nanosheets; Carbon; Mesoporosity; Metal nanoparticles Abstract A two-dimensional electrode architecture of ~25 nm sized Co nanoparticles chemically bonded to ~100 nm thick amorphous porous carbon nanosheets (Co@PCNS) through interfacial Co‒C bonds is reported for the first time. This unique 2D hybrid architecture incorporating multiple Li-ion storage mechanisms exhibited outstanding specific capacity, rate performance and cycling stabilities compared to nanostructured Co3O4 electrodes and Co-based composites reported earlier. A high discharge capacity of 900 mAh/g is achieved at a charge-discharge rate of 0.1C (50 mA/g). Even at high rates of 8C (4A/g) and 16C (8A/g) Co@PCNS demonstrated specific capacities of 620 and 510, mAh/g respectively. Integrity of interfacial Co‒C bonds, Co nanoparticles and 90% of the initial capacity are preserved after 1000 charge-discharge cycles. Implementation of Co nanoparticles instead of Co3O4 restricted Li2O formation during the charge-discharge process. In-situ formed Co‒C bonds during the pyrolysis steps improves interfacial charge transfer, and eliminate particle agglomeration; identified as the key factors responsible for the exceptional electrochemical performance of Co@PCNS. Moreover, nanoporous microstructure and 2D morphology of 1 ACS Paragon Plus Environment

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carbon nanosheets facilitate superior contact with the electrolyte solution and improved strain relaxation. This study summaries design principles for fabricating high-performance transition metal based Li-ion battery hybrid anodes.

1. Introduction Rechargeable Li-ion batteries are the most promising power sources in current generation of portable electronics, medical devices and electric vehicles.1-8 Despite of their several advantages, their energy density, and rate performance are not sufficient to meet the requirements of next generation power hungry devices and electric vehicles.9-10 The sluggish electrochemical performance of graphite anodes in current generation Li-ion batteries at high charge-discharge rates is due to slow Li+ diffusion in 10-20 micrometer diameter particles.11 These graphitic electrodes composed of ordered graphitic layers limit the energy/power density due to limited Li-storage capability (theoretical capacity of 372 mAh/g). Additionally, lithiation of graphite anodes at potentials (