Nitrogen pinning promoted highly reversible TiNb2O7-graphene anodes for lithium-ion batteries

Breaking through charge/mass transfer capability of electrode materials is a key step in achieving high-power and high-energy density lithium-ion batteries. Herein, nitrogen pinning is introduced into TiNb₂O₇-graphene composite anodes (TNO@NG) to enhance heterogeneous interfacial interactions and promote intrinsic carrier transport capability. Experiments and theoretical calculations show that nitrogen pining can introduce impurity energy levels and reconstruct electron distribution at heterogeneous interface, thereby improving electronic conductivity and reducing lithium ions migration energy barrier. Therefore, N-pinning achieves accelerated reaction kinetics and electrochemical reversibility of TNO@NG anodes. As a consequence, the TNO@NG anode exhibits outstanding electrochemical lithium storage capacity and rate capability, reaching high capacity of 213.9 mAh g^-1 at 10 C after 2000 cycles and 226.4 mAh g^-1 at 20 C. Moreover, the TNO@NG//LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) full cell can deliver a high capacity of 104.2 mAh g^-1 at 10 C. Importantly, this work will provide guidance for the construction and design of oxide-carbonaceous composites.