Reversible uniform and fine deposition stabilizing zinc anode at low temperature

The performance of low-temperature aqueous zinc metal batteries (AZMBs) is significantly hindered by the elevated freezing point of the aqueous electrolyte and the sluggish kinetics associated with Zn2+/Zn deposition/stripping reactions on the Zn anode. Here, we reported a functionalized electrolyte inducing a reversible uniform and fine deposition on Zn anode, which significantly enhances the low-temperature cyclic stability of Zn anode and AZMBs. The ethylene glycol and L-cysteine (L-Cys) in the electrolyte works together to achieve this goal. Specially, the L-Cys was found to be primarily responsible for rapid desolvation of Zn2+ and uniformly compact deposition of fine zinc particles at the interface. The Zn||Zn symmetric batteries demonstrate an extended operational lifespan exceeding 2,000 hours at a high rate and substantial area capacity of 10 mA cm−2 and 10 mA h cm−2, along with an impressive depth of discharge of 86.2% over a duration of 300 hours under ambient conditions. When at low temperature (-20 ℃), the Zn||Zn symmetric battery exhibits a remarkable cyclic stability for over 4,000 hours at both 1 mA cm−2 and 1 mA h cm−2, while Zn||ZnxV2O5·H2O full cell can last 1,000 cycles. In addition, the pouch battery demonstrates an impressive 95% capacity retention even after undergoing 540 cycles. This study presents a fresh outlook on enhancing the performance of AZMBs at low temperatures.