Proton insertion materials have generated significant attention due to their high durability, cost-effectiveness, and environmental friendliness in the field of electrochemical energy storage. The unique chemico-physical properties of protons (with the smallest ionic radius and lightest ionic mass) enable ultrafast ion diffusion kinetics, making these materials suitable candidates to meet the power density and energy density requirements for large-scale electrochemical energy storage. However, there still a long way to go to obtain both high energy density and high power density in proton batteries. It is crucial to gain deeper insights into the conduction mechanism and dynamics, which has driven extensive research into electrode materials.
Among these materials, tungsten oxide dihydrate (WO3.2H2O) and molybdenum oxide dihydrate (MoO3.2H2O) have been considered as particularly ideal candidates with advantages of high specific capacity, excellent cyclability, and fast proton diffusion. As metal oxides with simple crystal structures, they are well-suited as a starting point for exploration.
We are using a polymer-templating method to generate nanostructures of these tungsten and molybdenum oxides, with the aim of enhancing proton storage and transfer through higher surface areas. We will report on their structural characterisation by X-ray powder diffraction (XRPD) and electron microscopy, and their reversible redox processes and proton insertion/desertion behaviour by cyclic voltammetry (CV). These results will inform the next stage of our project involving ab initio molecular dynamics (AMID) calculations and synchrotron and neutron spectroscopy experiments, helping us build a comprehensive picture of the composition-structure-property relationships that underlie proton insertion and conduction. The ultimate goal to propose rational chemical modifications to optimise the proton charge and discharge rate, capacity and cyclability for possible real-world energy-storage applications.