Strategy for capacity boosting in aluminum-ion batteries: controlling the interlayer spacing

Abstract

Al-ion batteries (AIBs) have attracted increasing attention due to their three-electron reactions, abundant raw materials, and inherent safety. They employ cathodes such as graphite-based compounds and metal dichalcogenides, among which molybdenum disulfide (MoS2) stands out with its unique layered structure, enhancing AIB capacity. Notably, its 6.2 & Aring; interlayer spacing enables rapid ion diffusion, insertion, and extraction. However, few studies have explored the relationship between areal capacity and interlayer spacing in layered MoS2 for AIBs. Herein, interlayer-controlled MoS2 was synthesized via amine intercalation to enhance ion transport. The resulting n-butylamine-intercalated MoS2 exhibited a larger interlayer spacing of 10.1 & Aring; and achieved similar to 15-fold higher areal capacity than bulk MoS2. Moreover, it maintained 75 % of its initial capacity after 6000 cycles at 1.12 mA cm(-2), demonstrating excellent long-term stability. These findings contribute to high-performance AIB development using transition-metal sulfide cathodes.