TRANSITION METAL NANOPARTICLES ANCHORED ON CARBON ANODES FOR ADVANCED LI-ION STORAGE

摘要

Due to their superior energy density, rate capabilities and wide range of applications in portable electronics, medical implants, and electric cars etc., rechargeable Li-ion batteries are favorable candidates for electrochemical energy storage. Despite many advantages, use of graphite anodes (specific capacity of 372 mAh/g) limits their power density and specific capacity, which is essential for a number of commercial applications including rechargeable electric vehicles. Lithiation of graphite anodes at lower potentials (<0.3 V vs Li ~+/Li) also results in lithium dendrite growth and thereby challenging the overall safety of Li-ion batteries. Consequently, extensive research has been dedicated for the development of alternative high-capacity transition metal or metal oxide anode materials. Oxides of cobalt and manganese are attractive anode material for Li-ion batteries due to their high specific capacities. However, the implementation of these transition metal oxides is problematical due to poor electronic conductivity and cycling performance. Their poor cycling stability and rate performance is often associated with large volume change during charge-discharge process. Loss of electrical contacts and formation of electrochemically inactive clusters are other reasons for rapid capacity fading on prolonged cycling. It is therefore necessary to find a method to fabricate transition metal oxide anodes for Li-ion batteries.