Influences of conductive additives on electrochemical performances of artificial graphite anode with different shapes for lithium ion batteries

Abstract

Mesocarbon microbeads (MCMB) and needle coke (NC) with different shapes were selected to investigate the influences of conductive additives acetylene black (AB) and polyaniline (PAn). Experiments showed that the granularity distribution of spherical MCMB is narrow and does not contain small particles. Its electronic conductivity is lower than that of NC. Therefore, compared to NC, MCMB anode possesses a lower discharge capacity although their structural parameters are similar to each other. The addition of AB and PAn can improve the electrochemical performances of MCMB anode by enhancing the electronic conductivity of anode films. Owing to the fact PAn possessing a high electronic conductivity of 15.29 S cm −1, it plays a better role than AB. The discharge capacity of MCMB anode using 5 wt.% PAn reaches the maximum value of 341.1 mAh g −1. Excessive addition of PAn will hinder the dispersing of lithium ions and decrease the discharge capacity. The content of PAn and AB in MCMB anode conforms to the percolation theory. MCMB anode containing 5 wt.% PAn possesses the excellent cycle performance and small change of charge transfer resistance in the 30th cycle.