Achieving superior high-capacity batteries with the lightest Ti2C MXene anode by first-principles calculations: Overarching role of S-functionate (Ti 2CS2) and multivalent cations carrier

Finding thin, light and high-capacity electrode materials is an urgent need for the application of rechargeable metal-ion batteries. The performance of MXenes as anode materials are largely determined by the surface terminal groups, and surface modification strategies are often used to improve their energy storage performance. Here S-functionalized Ti2C is designed and the properties of it as anode materials for rechargeable metal-ion batteries is studied by first-principles calculations, including Li-, Na-, K-, Mg-, Ca-, and Al-ion batteries. The metallic nature, high structural stability of Ti2CS2 monolayer, as well as the small diffusion barriers and low OCV values of these metal cations make the Ti2CS2 monolayer a promising anode material for rechargeable metal-ion batteries. Most importantly, the stable multilayer adsorption (up to three layers) of Na and Mg ensure the excellent capacity of Ti2CS2 monolayer in Na-ion (935.57 mA h g−1) and Mg-ion (1871.13 mA h g−1) batteries. The findings in our work may encourage further experimental and theoretical research on the designation of MXenes-based, even other two-dimensional anode materials for high-capacity rechargeable metal-ion batteries.