Critical factors to inhibit water‐splitting side reaction in carbon‐based electrode materials for zinc metal anodes

• DOI: 10.1002/cey2.254
• Publication Date: 2022-07-21T06:59:56Z
• Authors: Dong Hyuk Kang; Eunji Lee; Beom Sik Youn; Son Ha; Jong Chan Hyun; Juhee Yoon; Dawon Jang; Kyoung Sun Kim; Hyungsub Kim; Sang Moon Lee; Sungho Lee; Hyoung‐Joon Jin; Hyung‐Kyu Lim; Young Soo Yun
• Keywords: TK1001-1841; multivalent ion; Production of electric energy or power. Powerplants. Central stations; carbon electrode; zinc metal anode; 01 natural sciences; 7. Clean energy; aqueous batteries; hydrogen evolution reaction; 0104 chemical sciences

AbstractZinc metal anodes (ZMA) have high theoretical capacities (820 mAh g−1 and 5855 mAh cm−3) and redox potential (−0.76 V vs. standard hydrogen electrode), similar to the electrochemical voltage window of the hydrogen evolution reaction (HER) in a mild acidic electrolyte system, facilitating aqueous zinc batteries competitive in next‐generation energy storage devices. However, the HER and byproduct formation effectuated by water‐splitting deteriorate the electrochemical performance of ZMA, limiting their application. In this study, a key factor in promoting the HER in carbon‐based electrode materials (CEMs), which can provide a larger active surface area and guide uniform zinc metal deposition, was investigated using a series of three‐dimensional structured templating carbon electrodes (3D‐TCEs) with different local graphitic orderings, pore structures, and surface properties. The ultramicropores of CEMs are the determining critical factors in initiating HER and clogging active surfaces by Zn(OH)2 byproduct formation, through a systematic comparative study based on the 3D‐TCE series samples. When the 3D‐TCEs had a proper graphitic structure with few ultramicropores, they showed highly stable cycling performances over 2000 cycles with average Coulombic efficiencies of ≥99%. These results suggest that a well‐designed CEM can lead to high‐performance ZMA in aqueous zinc batteries.