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Aqueous Rechargeable Zinc/Aluminum Ion Battery with Good Cycling Performance ̂
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Faxing Wang,†,‡,§ Feng Yu,†,∥ Xiaowei Wang,‡ Zheng Chang,‡ Lijun Fu,*,§ Yusong Zhu,*,§ Zubiao Wen,*,∥ Yuping Wu,*,‡,§ and Wei Huang‡ ‡
College of Energy, Institute for Electrochemical Storage, and Institute for Advanced Materials, Nanjing Tech University, Nanjing, Jiangsu 211816, People’s Republic of China § New Energy and Materials Laboratory (NEML), Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, People’s Republic of China ∥ College of Chemistry and Chemical Engineering, Jiangxi Normal University, Nanchang, Jiangxi 330022, People’s Republic of China S Supporting Information *
ABSTRACT: Developing rechargeable batteries with low cost is critically needed for the application in large-scale stationary energy storage systems. Here, an aqueous rechargeable zinc//aluminum ion battery is reported on the basis of zinc as the negative electrode and ultrathin graphite nanosheets as the positive electrode in an aqueous Al2(SO4)3/Zn(CHCOO)2 electrolyte. The positive electrode material was prepared through a simple electrochemically expanded method in aqueous solution. The cost for the aqueous electrolyte together with the Zn negative electrode is low, and their raw materials are abundant. The average working voltage of this aqueous rechargeable battery is 1.0 V, which is higher than those of most rechargeable Al ion batteries in an ionic liquid electrolyte. It could also be rapidly charged within 2 min while maintaining a high capacity. Moreover, its cycling behavior is also very good, with capacity retention of nearly 94% after 200 cycles. KEYWORDS: aqueous rechargeable battery, graphite, Zn negative electrode, nanosheet, rapid charge, intercalation
1. INTRODUCTION Recently, many new types of aqueous rechargeable batteries have been extensively invented, such as aqueous rechargeable lithium battery (ARLB),1−11 aqueous rechargeable sodium battery (ARSB),12−15 FeOx//Ni(OH)2,16 aqueous Zn ion battery,17,18 Zn//Ni(OH)2 or NiO battery,19,20 and KCuFe(CN)6//PPy@activated carbon (AC) battery.21 These aqueous rechargeable batteries are inherently safe by avoiding flammable organic electrolyte solutions. Moreover, aqueous electrolytes are not expensive, and the assembly process of the batteries is also easy. In addition, the ionic conductivity of aqueous electrolytes is high, about 2 orders of magnitude higher than those of organic electrolytes, which ensures high rate capability and, thus, high power density.8,21 In comparison to the key factors, such as energy density and cyclability, when a battery is used in portable electronic devices, the cost and safety are relatively more important in large-scale stationary energy storage systems, such as smart grids. With this in mind, the aqueous rechargeable batteries show potential application in stationary energy storage systems. In the past several years, the rechargeable aluminum (Al) ion battery in non-aqueous electrolytes was proposed.22−27 It shows some advantages over the Li or Na ion battery. First, aluminum is the most abundant metal element and the third © 2015 American Chemical Society
most abundant element in the Earth’s crust. Second, an aluminum-based redox couple engages a three-electron transportation during the electrochemical charge/discharge reactions, which offers viable storage capacity relative to the Li or Na ion battery from a single electron. V2O5,22,23 VO2,24 conducting polymers (polypyrrole and polythiophene),25 fluorinated graphite,26 and graphite27 have been shown to be promising electrode materials for the Al ion battery in an AlCl3/ionic liquid electrolyte. For example, the Al//graphitic foam battery in an AlCl3/1-ethyl-3-methylimidazolium chloride electrolyte exhibited a stable cycling life up to 7500 charge/ discharge cycles without decay at ultrahigh current densities.27 Although this study represents a milestone for the development of a secondary Al ion battery, the use of ionic liquids as the electrolyte makes its cost high. Moreover, its specific capacity is low (only 60 mAh g−1). Therefore, the development of new types of less-expensive rechargeable batteries with high specific capacity is of great significance and challenging. One of the innovative strategies is shifting from an expensive ionic liquid electrolyte to a cheap aqueous electrolyte. Currently, only TiO2 Received: July 8, 2015 Accepted: December 30, 2015 Published: December 30, 2015 9022
DOI: 10.1021/acsami.5b06142 ACS Appl. Mater. Interfaces 2016, 8, 9022−9029
Research Article
ACS Applied Materials & Interfaces
Figure 1. (a) Formation mechanism for ultrathin graphite nanosheets and (b) XRD patterns of pristine graphite and graphite after expansion.
Figure 2. SEM micrograph of (a) pristine graphite and (b) graphite nanosheets and TEM micrograph of (c) pristine graphite and (d) graphite nanosheets.
nanotubes28 and prussian blue analogues29,30 show the ability to insert an aluminum ion reversibly in aqueous electrolytes. However, both of them also deliver low specific capacity (
