Boron doped Ti2Nb10O29 nanosheets core/shell arrays as advanced high-energy anode for fast lithium ions storage

Abstract

Titanium niobium oxide (Ti₂Nb₁₀O₂₉, TNO) as anode for high-energy lithium ion batteries (LIBs) typically suffers from sluggish kinetics and reaction activity because of its inferior electronic/ionic conductivity and easy aggregation feature. Herein, we present a novel synergistic strategy to tackle such problems of TNO by combining boron (B) doping and porous carbon nanosheet (PCN) arrays support. Experiment results and theoretical calculations demonstrate that the doped B substantially ameliorates the intrinsic electronic/ionic conductivity of TNO, increases the oxygen vacancy content in TNO, and accelerates lithium ion diffusion. Meanwhile, high-conductive PCN arrays as growth skeleton can avoid the agglomeration of B-TNO particles. As a result, the as-prepared PCN/B-TNO anode delivers an impressive specific capacity of 303 mAh g⁻¹ at 1 C and 104 mAh g⁻¹ at 20 C, superior to the PCN/TNO anode. Additionally, PCN/B-TNO anode also possesses a prominent long-time durability (85 % capacity retention after 2000 cycles). Our work paves a new way of rationally constructing high-energy anodes for fast energy storage and release.