Hybrids of LiMn2O4 nanoparticles anchored on carbon nanotubes/graphene sheets as long-cycle-life cathode material for rechargeable hybrid aqueous batteries

Abstract

A hybrid LiMn2O4-graphene-carbon nanotubes (LMO-GN-CNT) material is synthesized successfully by a facile hydrothermal method. The 15-nm-nanosized LiMn2O4 (LMO) particles anchor uniformly in the cross-linked conductive graphene (GN) and carbon nanotubes (CNT) matrix in the LMO-GN-CNT composite. Rechargeable hybrid aqueous batteries (ReHABs) are assembled by using LMO-based materials as cathodes and zinc metal as anodes. Galvanostatic charging/discharging cycles of the LMO-GN-CNT composite are performed in rechargeable hybrid aqueous batteries (ReHABs) in comparison of LMO-GN composite and pristine LMO material. Electrochemical measurements indicate that the LMO-GN-CNT composite exhibits superior rate capability and cycle ability. The initial discharge capacity of 129 and 100 mAh g−1 can be delivered at 0.2 and 5.0 C. The discharge capacity is still above 93 mAh g−1, and capacity retention of over 82.1% is obtained after 600 cycles at 2.0 C. The satisfactory electrochemical properties can be ascribed to the little aggregation and good dispersion of the nanosized LMO particles and the introduction of GN and CNT, which can enhance the conductivity, shorten the diffusion length of electrolyte, and provide a large specific surface area for lithium storage.