Lithium-ion batteries (LIBs) have facilitated the widespread popularity and use of portable electronic devices for nearly three decades. They are now enabling the revolutionary migration to electric vehicles and also playing a pivotal role in the realization of grid-scale battery storage. LIBs enjoy very high gravimetric and volumetric energy densities due to lithium being a light element, well-optimized battery chemistry, and high-performance electrode and electrolyte materials. Graphite has been the material of choice for anodes in LIBs with graphite/silicon composites getting more traction in recent times due to much higher theoretical capacities albeit with its own challenges. New materials need to be constantly evaluated in order to devise better batteries to make them more energy dense, safer, cheaper, and more environmentally friendly.

Here, the electrochemical performance of Y₂W₃O₁₂ - synthesized using the solid-state methods - is probed as the active anode material in LIBs. The materials from this family have a framework structure with large voids which can potentially store alkali ions during electrochemical cycling without a significant change in volume. However, the electrodes prepared with as-synthesized Y₂W₃O₁₂ powder experience a significant drop in capacity possibly due to the inherently poor conductivities and resultant loss of conduction pathways as the cycling progresses.

In this work, we investigated the impact of facile post-synthesis modifications such as milling and carbon coating on the electrochemical performance in terms of capacity retention during long-term cycling and also the rate performance in a half-cell setup. In particular, carbon coating is shown to result in significant performance enhancement in both the unmilled and milled samples suggesting that impact of carbon coating can be more significant than milling in these systems. At 100 mA/g, the Coulombic efficiency during the 1^st cycle jumped from 35% for the unmilled/uncoated sample to >60% for the carbon coated samples. Furthermore, the 1^st lithiation capacities for the different variants of the material were quite similar and ranged between 600-700 mAh/g. However, the differences in 1^st delithiation capacities were quite remarkable at 226 and 425 mAh/g for the unmilled/uncoated and carbon coated samples, respectively. The carbon coated samples displayed excellent capacity retention at currents as high as 400 mAh/g. The promising results obtained from this study could be translated to other members of this family of materials and to a wider scope of materials.