Computational Design of Hydrogenated Monolayer Pyrite for Enhanced Energy Storage

Abstract

In the search for clean energy technologies, it is crucial to develop low-cost batteries with enhanced performance, and 2D materials are promising for electrode applications owing to their high surface area where fast ionic diffusion can occur. In this work, density functional theory calculations that demonstrate the great potential of recently synthesized 2D pyrite as a battery electrode are reported. An extensive analysis of its performance toward Li-ion batteries and post-lithium technologies (Na, K, Mg, Ca, Zn, Al), as well as how point defects can be leveraged to engineer its electronic properties are reported. First, the results explain that the main drawback of the unmodified material, namely its voltammetric peaks at high voltages, is due to the overly strong adsorption of lithium ions. Second, it is demonstrated that hydrogenation of the material leads to milder open-circuit voltages without compromising the capacity of the anode, and lowers the diffusion barrier to only 0.06eV for both Li and K ions. With a capacity as high as 1317 mAh g⁻¹ for Al-ion, hydrogenated monolayer pyrite is demonstrated to be a promising material for energy storage applications.