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.
