Nanosheet architecture of MnO2/carbon with improved reaction kinetics toward advanced zinc energy storage

Abstract

Aqueous zinc ion batteries (AZIBs) hold substantial promise for large-scale energy storage system by virtue of their good safety and cost-effectiveness. However, the typical cathode material of MnO2 is practically hampered by poor rate/cycling performance owing to its low electrical conductivity and structural fragility. Herein, a nanosheet architecture of MnO2/carbon is constructed via in situ rooting MnO2 nanoarrays on carbon substrate to achieve high-rate and long-durable zinc energy storage. The unique nano-architecture significantly promotes the reaction kinetics by supplying plentiful active sites, short diffusion pathways, and improved charge transfer conductivity. The advantageous features endow the MnO2/carbon with remarkable rate capability (175 mAh/g at 3.0 A/g) and excellent cycling lifespan (87.8 % capacity retention after 1000 cycles at 1.0 A/g). In addition, the kinetic enhancement and fundamental reaction mechanism are systematically investigated. The encouraging results will shed new insight on designing MnO2-based materials to advance the development of AZIBs.