Yttrium-doped MnO2/rGO composites as cathode material for ultra-long cycle life aqueous zinc-ion battery

Abstract

Manganese dioxide, functioning as a cathode material for aqueous zinc-ion batteries (AZIBs), demonstrates a variety of benefits, such as elevated theoretical specific capacity, outstanding electrochemical performance, environmental compatibility, ample resource availability, and facile modification. These advantages make MnO₂ one of the cathode materials that have attracted much attention for AZIBs. Nevertheless, manganese dioxide cathode in practical applications suffers from structural instability during the cycling process because of sluggish electrochemical kinetics and volume expansion, which hinder their large-scale application. Doping and compositing with conducting frameworks is an effective strategy for improving structural stability. Herein, homogeneously in situ growth of Yttrium-doped MnO₂ nanorods on conductive reduced graphene oxide (Y-MnO₂/rGO), were synthesized through a straightforward hydrothermal method. The Y-MnO₂/rGO electrodes have an ultra-long cycle life of 179.2 mA h g⁻¹ after 2000 cycles at 1 A g⁻¹ without degradation. The excellent structural stability is attributed to the cooperative effect of yttrium doping and compositing with rGO, which is an effective approach to enhance the stability and mitigate the Jahn–Teller distortion associated with Mn ions.