Q.T. Qu

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

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.

Materials for lithium-ion batteries by mechanochemical methods

Abstract: Lithium-ion batteries have many advantages over traditional rechargeable batteries and their development has been very rapid. In this chapter, preparation and electrochemical performance of their key materials including cathode materials such as LiCoO 2 and LiMn 2 O 4 , anode materials such as carbon, alloys and nitrides, and electrolytes such as oxides and sulfides by mechanochemical (MC) methods are primarily summarized. Compared with conventional solid state reactions at high temperature, the MC methods appear to accelerate and simplify the synthesis process and decrease the energy expenses as well as the cost of the material. In addition, the prepared materials present good electrochemical performance. When MC methods are combined with other techniques, their advantages can be more fully displayed. In the meanwhile, MC reactions will have some unfavourable actions to some materials which should be avoided. Finally, some further aplications for MC methods in lithium-ion batteries are pointed out.