Electrolyte Design for In Situ Construction of Highly Zn2+‐Conductive Solid Electrolyte Interphase to Enable High‐Performance Aqueous Zn‐Ion Batteries under Practical Conditions

다국어 초록 (Multilingual Abstract)

Rechargeable aqueous Zn‐ion batteries promise high capacity, low cost, high safety, and sustainability for large‐scale energy storage. The Zn metal anode, however, suffers from the dendrite growth and side reactions that are mainly due to the absence of an appropriate solid electrolyte interphase (SEI) layer. Herein, the in situ formation of a dense, stable, and highly Zn2+‐conductive SEI layer (hopeite) in aqueous Zn chemistry is demonstrated, by introducing Zn(H2PO4)2 salt into the electrolyte. The hopeite SEI (≈140 nm thickness) enables uniform and rapid Zn‐ion transport kinetics for dendrite‐free Zn deposition, and restrains the side reactions via isolating active Zn from the bulk electrolyte. Under practical testing conditions with an ultrathin Zn anode (10 µm), a low negative/positive capacity ratio (≈2.3), and a lean electrolyte (9 µL mAh−1), the Zn/V2O5 full cell retains 94.4% of its original capacity after 500 cycles. This work provides a simple yet practical solution to high‐performance aqueous battery technology via building in situ SEI layers.
A unique electrolyte design strategy for in situ solid electrolyte interphase (SEI) construction is proposed in aqueous Zn chemistry to stabilize the Zn–electrolyte interface. Apart from the realization of high Zn reversibility and utilization, the exploitation of the robust in situ SEI enables significantly enhanced cyclability of Zn/V2O5 full cells under practical conditions.