Development of a novel CNT-composited high entropy boride (MnFeCoNiZnAl)1/6B cathode material for ultra-stable and long-life sodium-ion batteries: DFT and experimental study

Abstract

In this work, we utilized density functional theory (DFT) computations to design and optimize a multi-component boride, (MnFeCoNiZnAl)_1/6B, which exhibited enhanced stability and charge storage capabilities. The synthesis process involved a liquid-phase method to create an amorphous (MnFeCoNiZnAl)_1/6B compound supported by carbon nanotubes (CNTs), resulting in improved electrochemical performance. Characterization data confirmed successful formation of the high-entropy boride and indicated a higher specific surface area and broader pore size distribution for the CNT-supported version. Computational models suggested that the high-entropy modification broadened the voltage window, enabling better matching with negative electrodes. Theoretical calculations estimated the maximum theoretical sodium-ion adsorption capacity and specific capacities, with (MnFeCoNiZnAl)_1/6B achieving the highest value of 827.69 mAh g^-1. The study demonstrates the successful fabrication of an innovative high-entropy boride-based cathode with excellent specific capacity and long-term cycling stability under high current loads, offering promise for large-scale energy storage applications as a cost-effective and safe alternative to lithium-ion batteries.