Ca <sub>2</sub> C MXene monolayer as a superior anode for metal-ion batteries
Kaptan Rajput, Vipin Kumar, Siby Thomas, Mohsen Asle Zaeem, Debesh R. Roy
Abstract
Abstract Rechargeable batteries can effectively mitigate the increasing crisis associated with clean energy storage technologies. The alkali metal-ion based rechargeable batteries require a low diffusion barrier, a low average open-circuit voltage (OCV), and a high storage capacity for their superior performance. Using comprehensive first-principle calculations, we demonstrate that calcium carbide monolayer (Ca 2 C-ML) MXene meets all the aforementioned criteria and is a superior anode material for lithium (Li), sodium (Na), and potassium (K) metal-ion batteries. By first-principles calculations, the structural and electronic properties of Ca 2 C-ML and its extensive ion battery applications are studied. The adsorption properties of Li, Na, and K alkali ions on the Ca 2 C-ML sheet confirm excellent charge transfer and electrical conductivity. The ultra-low diffusion barriers of 0.027, 0.059, and 0.028 eV for Li, Na, and K alkali ions, respectively, indicate the superior mobility and fast cycling caliber (metal adsorption and desorption) of the Ca 2 C-ML. The OCV of the Ca 2 C-ML is 0.10, 0.24, and 0.28 V for Li, Na, and K-ions, respectively, ensuring a better battery performance. The specific capacity of 582 mAh g −1 is achieved for all three cases, which is much higher than that of a traditional graphite anode with Li, Na, and K ions. The volume expansion during the intercalation is negligible for all three cases, indicating long term structural integrity of the anode using Ca 2 C-ML. Our investigations suggest that the newly designed 2D Ca 2 C-ML is a suitable anode candidate for use in the next-generation of high-performance Li, Na, and K-ion batteries.