Elimination of the lithiated rutile impurity phase to deliver higher-quality directly recycled TiNb2O7 anodes

The development of efficient recycling processes for lithium-ion battery electrode materials is essential for sustainable battery technologies. TiNb 2 O 7 (TNO) is an attractive high-power anode material, but recycling strategies remain largely unexplored. Here, we report a direct recycling approach for TNO anodes recovered from a cycled TNO/LiNi 0.6 Mn 0.2 Co 0.2 O 2 cell. We find that residual lithium in recovered TNO promotes the formation of a lithiated rutile impurity phase and Ti 2 Nb 10 O 29 during thermal processing, which degrades the electrochemical performance of the recovered TNO. Structural and compositional analyses reveal the origin of these phases and guide the development of a recycling route that combines hydrothermal lithium removal with a subsequent heat treatment, preventing impurity formation. Recycled TNO produced by this method delivers high capacity, excellent rate capability, and stable performance at high current densities, achieving 279 (5) and 261 (10) mA h g −1 at 2 and 4 A g −1 , respectively, comparable to commercial TNO. These results demonstrate a viable direct recycling strategy for TNO anodes.