Carbon-Confined Tellurium Nanotube Cathodes Enabling Stable Aluminum-Ion Batteries with High Capacity

Tellurium (Te) has emerged as a promising cathode material for aluminum-ion batteries (AIBs). However, its practical application is hindered by poor intrinsic electrical conductivity and the shuttle effect of soluble tellurium species. Herein, carbon-coated tellurium nanotube (TeNT@CT) was synthesized via a combined solvothermal-hydrothermal method followed by carbonization. The resulting TeNT@CT possesses a high specific surface area (35.1 m² g^-1) and a hierarchical porous structure, providing abundant active sites and promoting efficient electron and ion transport. Due to the synergistic confinement effect of the carbon shell on TeNT and the porous carbon layer on the modified separator, the TeNT@CT-based AIB exhibits outstanding electrochemical performance. It delivers an initial discharge capacity of 309 mAh g^{- 1} at 0.1 A g^{- 1} with a nearly 100% Coulombic efficiency. Notably, even after 1500 cycles at a current density of 2 A g^{- 1}, the electrode still delivers a stable discharge capacity of 93 mAh g^{- 1} with a Coulombic efficiency above 97%, achieving an impressive capacity retention of 86.1%. This work offers an effective strategy for suppressing the shuttle effect in soluble chalcogen-based cathodes for AIBs and underscores the potential of rationally designed carbon-modified Te nanostructures for high-performance multivalent-ion battery systems.