Diatomite-like KFeS₂ for Use in High-Performance Electrodes for Energy Storage and Oxygen Evolution

Bifunctional materials possess remarkable properties that allow them to store and convert electrical energy easily. In this paper, diatomite-like potassium iron disulfide (KFeS₂) was synthesized by a multistep sacrificial template method, and its morphological, electrochemical, and oxygen evolution reaction (OER) properties were investigated. KFeS₂ was found to be porous, hollow, and cake-like, which suggests a high specific surface area (SSA) and abundant electrochemically active sites. A very high specific capacitance of 651 F g^-1 at 1.0 A g^-1 was also obtained due to the substance's unique structure and high porosity. Additionally, the diatomite-like KFeS₂ possessed a very low overpotential ƞ₁₀ of 254 mV at a current density of 10 mA cm^-2 and a small Tafel slope of about 48.4 mV dec^-1. Thus, the diatomite-like KFeS₂ demonstrates broad application prospects for both energy storage and conversion.