Low-temperature and high-rate Zn metal batteries enabled by mitigating Zn2+ concentration polarization

Despite of the thriving development of rechargeable batteries, the realization of high-rate batteries at low temperature remains challenging. Herein, low-temperature and high-rate Zn metal batteries (ZMBs) are successfully developed by regulating electrolyte chemistry. Zn2+ concentration polarization is first revealed to be the kinetic restriction of nonaqueous high-rate ZMBs at low temperature. Furthermore, by using an acetonitrile/water co-solvent electrolyte, the Zn2+ solvation structure is modulated with effectively promoted ion pairs dissociation and decreased size of Zn2+ solvation shell, thus greatly promoting Zn2+ transport and mitigating Zn2+ concentration polarization. Consequently, stable cycling for over 500 h of Zn-Zn symmetric batteries at 5 mA cm−2 under − 40 °C or at 10 mA cm−2 under −20 °C is achieved. This superior kinetics and high cumulative cycling capacity reach a record level among the reported low-temperature ZMBs. Moreover, the high-rate V2O5-Zn full batteries under −40 °C also exhibit great prospect of practical application.