Encapsulating Oxygen‐Deficient TiNb 24 O 62 Microspheres by N‐Doped Carbon Nanolayer Boosts Capacity and Stability of Lithium‐Ion Battery

Abstract Most of the insertion anode materials are approaching their specific capacity limitations. TiNb 24 O 62 , combining the merits of high theoretical capacity, large working potential and excellent safety, is a promising candidate for lithium‐ion batteries (LIBs). However, its poor intrinsic conductivity and relatively sluggish reaction kinetics hinder its wide applications. Herein, we encapsulate the oxygen‐deficient TiNb 24 O 62 microspheres by highly conductive N‐doped carbon nanolayer (DTNO@NC), where TiNb 24 O 62 is purposely made to exhibit oxygen deficiency, by aerosol spray followed by co‐carbonization of the electronically coupled polydopamine (PDA) coating layer. The oxygen‐deficient engineering for TiNb 24 O 62 improves the intrinsic conductivity and active sites, while the PDA derived N‐doped carbon coating layer not only stabilizes the interface between the electrode and electrolyte, but also further enhances the overall conductivity. As a result, the as‐fabricated DTNO@NC electrode delivers excellent Li + ion storage capacity (270 mAh g −1 at 0.1 A g −1 ) and superior cycling lifespan (capacity retention of 90 % after 1000 cycles). This work demonstrates the effectiveness of integrating an oxygen‐deficient structure of intercalation‐type anode material with a carbon encapsulating nanolayer in enabling the overall energy storage performance.