Application of purified kish flake graphite as a potential cathode material for high-performance aluminum ion batteries

The separation and purification of kish graphite is an important prerequisite for its high value and com-prehensive utilization. The comprehensive separation process including water washing dust removal, magnetic separation and acid leaching purification can effectively enrich and purify kish flake graphite (KFG) from low-cost industrial by-product kish graphite. When the magnetic strength is 2000 Gauss, the purified KFG has suitable recovery (57.34%), high fixed carbon content (99.38%) and low ash content (0.62%). Compared with natural flake graphite, KFG has a highly ordered graphite microcrystalline layer structure with higher graphitization degree (99.77%) and well-developed micro/nanopore with larger specific surface area (4.12 m2 center dot g-1). Such distinctive microstructure features ensure KFG to be applied as a cathode material for aluminum ion batteries (AIBs) to exhibit superior electrochemical behaviors. KFG exhibits a high re-versible specific capacity (110.7 mAh/g at 50 mA/g), outstanding rate capability (56.9 and 26.6 mAh/g at high current densities of 1000 and 2000 mA/g) and superior long-term cycling stability (101.8 mAh/g with a Coulombic efficiency of 99.5% at 1000 mA/g after 2000 cycles). This study demonstrates a promising fea-sibility for mass production of KFG from industrial by-product kish graphite for high performance AIBs. (c) 2023 Elsevier B.V. All rights reserved.