Cathodic Zn underpotential deposition: an evitable degradation mechanism in aqueous zinc-ion batteries

• DOI: 10.1016/j.scib.2022.08.023
• Publication Date: 2022-08-20T23:34:20Z
• Authors: Shaohua Zhu; Yuhang Dai; Jinghao Li; Chumei Ye; Wanhai Zhou; Ruohan Yu; Xiaobin Liao; Jiantao Li; Wei Zhang; Wei Zong; Ruwei Chen; Guanjie He; Dongliang Chao; Qinyou An
• Keywords: Aqueous battery; Zinc-ion battery; Zn metal deposition; Degradation mechanism; 01 natural sciences; 7. Clean energy; Underpotential deposition; 0104 chemical sciences

Aqueous zinc-ion batteries (AZIBs) are promising for large-scale energy storage, but their development is plagued by inadequate cycle life. Here, for the first time, we reveal an unusual phenomenon of cathodic underpotential deposition (UPD) of Zn, which is highly irreversible and considered the origin of the inferior cycling stability of AZIBs. Combining experimental and theoretical simulation approaches, we propose that the UPD process agrees with a two-dimensional nucleation and growth model, following a thermodynamically feasible mechanism. Furthermore, the universality of Zn UPD is identified in systems, including VO2//Zn, TiO2//Zn, and SnO2//Zn. In practice, we propose and successfully implement removing cathodic Zn UPD and substantially mitigate the degradation of the battery by controlling the end-of-discharge voltage. This work provides new insights into AZIBs degradation and brings the cathodic UPD behavior of rechargeable batteries into the limelight.