Catalytic graphitization of porous graphitic carbon derived from needle coke as anode materials for lithium-ion batteries

Abstract

In this work, potassium perferite (K2FeO4) is used as a catalyst in a straightforward and effective process of simultaneous activation and graphitization to create porous graphitized carbon (PGC), with coal-based green needle coke acting as starting material. The impacts of heating temperatures and K2FeO4 solution concentrations on the microstructure, morphology, and electrochemical lithium storage ability were thoroughly investigated. The as-synthesised PGC materials have a high specific surface area of 260.55 m2 g−1 and a good three-dimensional porous structure. Optimized PGC material synthesized at a temperature of 900 °C and concentrations of K2FeO4 solutions show excellent rate performance and cycling stability, making it a promising anode material for lithium-ion batteries (LIBs). At a current density of 100 mAg−1, it has a comparatively high specific discharge capacity of 386.05 mAh g−1 together with strong cycling stability (90.79% retention rate after 400 cycles). It maintains a discharge capacity of 325 mAh g−1 in the multiplicity test at a high current density of 1600 mA g−1. It takes less time, energy, and is much more efficient to complete the synchronous carbonization and graphitization of needle coke when potassium perferite is used as a catalyst, as opposed to traditional high-temperature graphitized technology and conventional two-step activation and graphitization strategy. The green needle coke-derived PGC materials include many active sites and defects, a high electrical conductivity, a shortened ion diffusion pathway, and a unique micro-mesoporous structure that makes them suitable electrode materials for lithium-ion batteries.