Porous LiMn2O4 as cathode material with high power and excellent cycling for aqueous rechargeable lithium batteries

Abstract

A porous LiMn₂O₄ consisting of nano grains was prepared by using polystyrene as template. It was studied as a cathode material for aqueous rechargeable lithium batteries (ARLBs) using 0.5 mol l⁻¹Li₂SO₄ aqueous solution as the electrolyte. Charge and discharge capacities at a current density of 10 A g⁻¹ (about 90C) were 76% and 95% of the total capacity (118 mAh g⁻¹), respectively. The power density can be up to 10000 W kg⁻¹ and the cycling behavior is excellent. After 10000 cycles at 9C with 100% DOD (depth of discharge), the capacity retention of porous LiMn₂O₄ is 93%, which indicates that it can be used for a lifetime without maintenance. The main reasons for its excellent electrochemical performance are due to the nano grains, porous morphology and high crystalline structure. In addition, the acid-free aqueous electrolyte prevents Mn²⁺ from dissolution. These excellent results suggest a great promise for the development of aqueous rechargeable lithium batteries (ARLBs) in practical application.