Free-Standing LiNi0.5Mn1.5O4/Carbon Nanofiber Network Film As Light-Weight and High-Power Cathode for Lithium Ion Batteries

Light-weight and high-power LiNi_0.5Mn_1.5O₄ / carbon nanofiber (CNF) network electrodes are developed as high voltage cathode for lithium ion batteries. The LiNi_0.5Mn_1.5O₄ / CNF network electrodes are free-standing and can be used as cathode without using any binder, carbon black or metal current collector, and hence the total weight of the electrode is highly reduced while keeping the same areal loading of active materials. Compared with conventional electrodes, the LiNi_0.5Mn_1.5O₄ / CNF network electrodes can yield up to 55% reduction in total weight and 2.2 times enhancement in the weight percentage of active material in the whole electrode. Moreover, the LiNi_0.5Mn_1.5O₄ / carbon nanofiber (CNF) network electrodes showed excellent current rate capability in the large current test up to 20C (1C = 140 mAh/g), when the conventional electrodes showed almost no capacity at the same condition. Further analysis of polarization resistance confirmed the favorable conductivity from CNF network comparing with conventional electrode structure. By reducing weight, increasing working voltage and improving large current rate capability simultaneously, the LiNi_0.5Mn_1.5O₄ / CNF electrode structure can highly enhance the energy/power density of lithium ion batteries, and thus holds great potential to be used with ultra-thin, ultra-light electronic devices as well as electric vehicles and hybrid electric vehicles.