Suppressing the Shuttle Effect via Polypyrrole-Coated Te Nanotubes for Advanced Na-Te Batteries.

There is a growing demand for research and development of advanced energy storage devices with high energy density utilizing earth-abundant metal anodes such as sodium metal. Tellurium, a member of the chalcogen group, stands out as a promising cathode material due to its remarkable volumetric capacity, comparable to sulfur, and significantly high electrical conductivity. However, critical issues arise from soluble sodium polytellurides, leading to the shuttle effect. This phenomenon can result in the loss of active materials, self-discharge, and anode instability. Here, we introduce polypyrrole-coated tellurium nanotubes as the cathode materials, where polypyrrole plays a crucial role in preventing the dissolution of polytellurides, as confirmed through operando optical microscopy. The polypyrrole-coated tellurium nanotubes exhibited an outstanding rate performance and long cycle stability in sodium-tellurium batteries. These research findings are anticipated to bolster the viability of polypyrrole-coated tellurium nanotubes as promising cathode materials, making a substantial contribution to the commercialization of sodium-ion battery technology.