Prelithiation treatment of graphite as cathode material for rechargeable aluminum batteries

Abstract

In this paper, the prelithiation graphite electrode material as a cathode material for rechargeable aluminum ion batteries was first successfully synthesized by treated with n-butyllithium. The morphology and microstructure of the electrode materials were characterized by SEM and TEM, respectively. The energy storage mechanism of aluminum ion batteries was confirmed by ex-situ XPS. It is found that not only AlCl4− but also Al3+ could also be intercalated and deintercalated into the prelithium graphite electrode material. The CV result clearly shows that the Graphite-Li electrode material has two pairs of redox peaks, which can be attributed to the AlCl4− and Al3+ intercalation and deintercalation into the electrode materials, respectively. In addition, the discharge specific capacity of Graphite-Li (68.2 mAh g−1) is significantly higher than Graphite (49.2 mAh g−1) at the currert density of 200 mA g−1. The discharge capacity of Graphite-Li can still reach 64 mAh g−1 even after 500 cycles with a coulombic efficiency close to 100%. Such remarkable electrochemical performance is attributed to the fact that the interlayer spacing is improved by prelithiation treatment which reduces the electrostatic effect between Al3+ or AlCl4− and electrode materials.