Chemically resistant Cu-Zn/Zn composite anode for long cycling aqueous batteries
Chemically resistant Cu-Zn/Zn composite anode for long cycling aqueous batteries
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DOI：
10.1016/j.ensm.2020.01.032
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发表时间：
2020-05-01
影响因子：
20.4
通讯作者：
Sun, Yongming
中科院分区：
文献类型：
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作者：
Cai, Zhao;Ou, Yangtao;Sun, Yongming
可充电水锌金属电池是可再生能源存储的理想选择。然而，金属锌具有化学活性，由于其低氧化还原电位，在水溶液中容易受到化学腐蚀。揭示锌金属阳极的腐蚀机理，提高锌金属阳极的化学稳定性和电化学可逆性，对锌金属阳极的实际应用具有重要意义。本研究揭示了锌金属电极在水溶液ZnSO4电解液中容易氧化，形成硫酸氢氧化锌和氢气，导致电池内阻增加和膨胀问题，最终导致电池失效。为了抑制这种化学腐蚀，在锌金属阳极中引入一种防腐金属Cu，构建结构致密、均匀的Cu/Zn复合材料，在电池循环过程中电化学转化为Cu-Zn合金/Zn复合材料。制备的Cu-Zn/Zn电极在1 mA/cm(2)和0.5 mAh/cm(2)下可稳定循环1500次以上，静置1个月后过电位变化不大（46 mV），而裸露的Zn电极在相同条件下电压波动大，过电位高（>400 mV），表明抑制Zn金属阳极对可充电水性电池的化学腐蚀的重要性。
Rechargeable aqueous Zn metal batteries are promising candidates for renewable energy storage. However, Zn metal is chemically active and suffers from chemical corrosion in aqueous electrolyte due to its low redox potential. It is of vital importance to reveal the corrosion mechanism, and improve the chemical stability and electrochemical reversibility of Zn metal anode for its practical application. In this work, it is revealed that a Zn metal electrode readily gets oxidized during its resting in aqueous ZnSO4 electrolyte, forming zinc hydroxide sulfate and hydrogen gas, leading to the increased internal resistance and swollen problems of batteries, and eventually battery failure. To inhibit such chemical corrosion, an anti-corrosive metallic Cu is introduced to Zn metal anode to construct a uniform Cu/Zn composite with dense structure, which is electrochemically converted to Cu-Zn alloy/Zn composite during battery cycling. The as-achieved Cu-Zn/Zn electrode exhibits stable cycling for over 1500 cycles at 1 mA/cm(2) and 0.5 mAh/cm(2) with little change in overpotential (46 mV) after resting for 1 month, while the bare Zn electrode shows large voltage fluctuation and high overpotential (>400 mV) under the same condition, suggesting the importance of inhibiting the chemical corrosion of Zn metal anode for rechargeable aqueous batteries.