Crystal Water Boosted Zn<sup>2+</sup> Transfer Kinetics in Artificial Solid Electrolyte Interphase for High-Rate and Durable Zn Anodes
Hongrun Jin, Simin Dai, Zehao Zhu, Yongxin Luo, Bei Qi, Kaisi Liu, Tao Wu, Xinyan Zhuang, Jun Zhou, Liang Huang
Abstract
The commercialization of aqueous zinc ion batteries (ZIBs) is seriously hindered by the inferior stability of the Zn anode, which principally originates from water-induced side reactions and dendrite issues. Interfacial engineering has been considered as a cost-effective way to tackle these bottlenecks. However, most artificial solid electrolyte interphase (SEI) suffers from sluggish Zn2+ migration and thus compromises the kinetic merits of aqueous ZIBs especially at ultrahigh rates. Herein, we present a unique H2O molecules-rich zinc phytate (PAZn) interphase for the optimization of Zn anodes. The critical role of crystal water on the Zn2+ transport process is demonstrated. Benefiting from the shielding effect, the Zn2+ diffusion coefficient increases by orders of magnitude in the presence of crystal water. Accordingly, the Zn anode modified by PAZn interphase delivers an impressive lifespan of 1200 h and dramatically reduced voltage hysteresis even under an ultrahigh current density of 10 mA cm–2, and it remains stable even at a higher Zn utilization exceeding 50%. Moreover, the V2O5//PAZn@Zn full cell exhibits remarkable performance with a high capacity retention of 89.3% after 600 cycles. This work provides an effective strategy for rationally designing highly Zn2+-conductive artificial SEI for durable Zn anodes and high-performance commercially available ZIBs.