Hydrolysis of Solid Buffer Enables High-Performance Aqueous Zinc Ion Battery.

Abstract

Aqueous zinc (Zn) ion batteries (AZIBs) have not yet fulfilled their talent of high safety and low cost since the anode/electrolyte interface (AEI) has long been impeded by hydrogen evolution, surface corrosion, dendritic growth, and by-product accumulation. Here, the hydrolysis of solid buffers is elaborately proposed to comprehensively and enduringly handle these issues. Take 2D layered black phosphorus (BP) as a hydrolytic subject. It is reported that the phosphoric acid generated by hydrolysis in an aqueous electrolyte produces a zinc phosphate (ZPO) rich solid electrolyte interphase (SEI) layer, which largely inhibits the dendrite growth, surface corrosion, and hydrogen evolution. Meanwhile, the hydrolytic phosphoric acid stabilizes the pH value near AEI, avoiding the accumulation of alkaline by-products. Notably, compared with the disposable ZPO engineerings of anodic SEI pre-construction and electrolyte additive, the hydrolysis strategy of BP can realize a dramatically prolonged protective effect. As a result, these multiple merits endow BP modified separator to achieve improved stripping/plating stability toward Zn anode with more than ten times lifespan enhancement in Zn||Zn symmetrical cell. More encouragingly, when coupled with a V2 O5 ·nH2 O cathode with ultra-high loadings (34.1 and 28.7mg cm-2 ), the cumulative capacities are remarkably promoted for both coin and pouch cells.