Zinc ferrum energy storage chemistries with high efficiency and long cycling life

Abstract

Energy storage systems with higher energy density and good electrochemical performance are the urgent demand of the new energy industry for electric vehicles. Rechargeable aqueous Zn-ion batteries (ZIBs) are particularly attractive owing to their safety, nontoxicity, inexpensiveness and high energy density. Here, we propose a new prototype of liquid Zn-ferrum batteries (ZFBs) using metal zinc as the anode, an aqueous Fe(II/III) redox couple as the catholyte, and modified carbon fibers with N and O (CF–N–O) as the positive electrode. This battery exhibits excellent electrochemical performance with a capacity of 352 mA h g⁻¹ at an average discharge voltage of up to 1.25 V, an energy density of 391 W h kg⁻¹, a power density of 2.2 kW kg⁻¹ at a current density of 2 A g⁻¹, and long cycling life.