# Tin Disulfide Nanosheet as Cathode Materials for Rechargeable Aluminum Ion Batteries: Synthesis, Electrochemical Performance, and Mechanism

## TL;DR

This paper explores tin disulfide nanosheets as a cathode material for rechargeable aluminum ion batteries, showing good performance and a clear energy storage mechanism.

## Contribution

The study introduces a scalable hydrothermal synthesis method for SnS2 and clarifies the Al3+ deintercalation mechanism through first-principles calculations.

## Key findings

- SnS2 nanosheets achieved 55 mAh g−1 capacity and 83% coulombic efficiency after 600 cycles.
- Al3+ prefers to deintercalate above sulfur atoms rather than between them, as revealed by first-principles calculations.

## Abstract

Aluminum ion batteries (AIBs) exhibit a promising development prospect due to their advantages such as high theoretical specific capacity, high safety, low cost, and sufficient raw material sources. In this work, nanosheet tin disulfide (SnS2) was successfully prepared using the hydrothermal method and then used as a cathode material for AIBs. The synthesized nano-flake SnS2 has a large size and thin thickness, with a size of about 900 nm and a thickness of about 150 nm. This electrode material effectively enhances the contact interface with the electrolyte and shortens the depth and travel distance of ion deintercalation. As an electrode, the battery obtained a residual discharge specific capacity of about 55 mAh g−1 and a coulombic efficiency of about 83% after 600 cycles. Furthermore, the first-principles calculation results show that the energy storage mechanism is the deintercalation behavior of Al3+. Based on model analysis and calculation results, it can be seen that compared with the position between two sulfur atoms, Al3+ is more inclined to be deintercalated directly above the sulfur atom. This study provides fundamental data for the large-scale preparation of AIBs using SnS2 as an electrode material and the application research of AIBs.