Dual‐Carbon Network for the Effective Transport of Charged Species in a LiFePO 4 Cathode for Lithium‐Ion Batteries

Cost and safety considerations have driven up the interest in LiFePO 4 as a lithium‐ion battery cathode material. Carbon nanopainting is currently the most common approach to increase the power density of LiFePO 4 , but more can be done to improve the application performance further. In this study the rate performance of LiFePO 4 was increased by using a conductive dual‐carbon network that can extract and conduct electrons from the Li + storage host more effectively than common pyrolyzed carbon. The dual‐carbon network consists of a connected network of graphene sheets and a nanoscale continuous coating of pyrolyzed conductive carbon on the surface of the aggregated LiFePO 4 nanocrystals. Such a construction supports fast electron transport between the aggregated LiFePO 4 nanocrystals as well as within them. Consequently the LiFePO 4 /C composite fabricated as such delivered very high rate performances even at very high discharge rates (104 mAh g −1 at 50  C where 1  C =170 mA g −1 ).