Porous ZnMn2O4 microspheres as a promising anode material for advanced lithium-ion batteries

Abstract

High-quality porous ZnMn₂O₄ microspheres composed of interconnected nanoparticles have been achieved by calcination of metal carbonates synthesized by a solvothermal reaction. The porous microspheres are characterized by XRD patterns, SEM, TEM, and HRTEM images to reveal the crystal phase and particle morphology. The porous structure and nanoscale building blocks of ZnMn₂O₄ microspheres make them a promising anode material for lithium ion batteries. After 300 cycles at a current density of 500 mA g⁻¹, they still preserve a reversible capacity of 800 mAh g⁻¹. Even at 2 A g⁻¹, the reversible capacity could be 395 mAh g⁻¹, higher than the theoretical capacity of graphite. The superior electrochemical performances can be associated with the porous structure and nanoscale building blocks, which promote the contacting between electrolyte and electrode, accommodate volume change during discharge/charge processes, and provide a large number of active surface sites for lithium storage.