Understanding the influence of nanocarbon conducting modes on the rate performance of LiFePO4 cathodes in lithium-ion batteries

Abstract

We report on an efficient and practical conducting mode built up by ternary conductive networks for boosting the rate performance of LiFePO4 (LFP) cathodes in lithium-ion batteries (LIBs). The influence on the electrical conductivity, rate capability and continuous ion channels of the resulting electrode are investigated. Carbon nanotubes (CNTs) with long-range electronic conduction are ultimately individually dispersed (mono-dispersed) into an electrode slurry, which connects the short-range conductive regions formed by graphene sheets. Importantly, CNTs provide more open channels for electron and ion transportation, than the blocking function of graphene sheets. Local graphene regions are herein bridged by mono-dispersed long CNTs to construct an efficient conductive network, enabling the composite to have improved fast electron/ion open channels. An efficient and practical conducting mode of “plane-to-line-to-point” is demonstrated to construct both short-/long-range electronic conduction and more open ion channels, while further contributing to conductive points all over the surface area of the LiFePO4 cathode.