The Nb–Ti–W–O system as safe high-power anodes for Li-ion batteries

Abstract

New materials are currently needed to serve as anodes in Li-ion batteries for applications that require extreme safety, long lifetimes, high power and improved energy density. High-power anodes based on niobium oxides are currently under investigation with Nb–Ti–O and Nb–W–O pseudobinaries having received much attention. To date, no material in the Nb–Ti–W–O system has been explored. Herein, 137 compositions are synthesized with numerous single-phase materials having been successfully made within the ternary. Many of these single-phase compositions demonstrate high performances, with the materials containing all of Ti, Nb and W outperforming the binary compositions. The highest room temperature discharge capacity of 315 mA h g⁻¹, and capacity retentions of 97% after several weeks of cycling represent a significant advancement over the performance previously seen in the binary mixtures. Importantly, performances at 37 °C are outstanding with retentions as high as 98.9%, showing high promise for implantable devices given their good performance at body temperatures.