Exploring New Cathode Materials to Enable High Energy Magnesium Batteries

Abstract

Modern smartphones, electric vehicles, drones, and other evolving technologies demand improvement of Li-ion batteries into more energy-dense power sources. Magnesium (Mg) batteries are a promising alternative because the Mg²⁺ ion shuttles twice as many electrons as Li⁺ , thereby doubling the theoretical volumetric energy density. Here, we investigate the storage capacity and Mg-ion hosting mechanisms of tungsten diselenide (WSe₂) as a cathode material for these cutting-edge battery systems. Using a three-electrode electrochemical setup, we measured a high specific capacity of 120 mAh/g and subsequently characterized the material at 0%, 50%, 75%, and 100% discharge via X-ray diffraction and Raman. Characterization showed no indications of Mg-WSe₂ conversion reactions, and the amount of intercalation of Mg²⁺ into WSe₂ remains uncertain. Further experimentation with more compatible electrolytes is necessary to confirm hosting mechanisms of WSe₂. This work opens a door to energy-dense multivalent ion batteries that surpass current lithium-ion technologies in cost, safety, and size.