Oxygen defect boosted N-doped Ti2Nb10O29 anchored on core-branch carbon skeleton for both high-rate liquid & solid-state lithium ion batteries

Abstract

Dual enhancement on electronic & ionic conductivity of Ti2Nb10O29 (TNO) electrodes is the key point to achieve high performance by promoting reaction kinetics with accelerated ion/electron transfer when applied in Li-ion batteries (LIBs). Herein, a powerful synergistic trinity strategy is proposed to construct integrated N-doped TNO@TiC/C-NC hierarchical electrodes, in which novel designed TiC/C-NC core-branch skeleton is used to load N-doped TNO (N-TNO) nanoparticles with symbiotic oxygen vacancy. The conductive hierarchical TiC/C-NC core-branch skeleton can not only enhance the electronic conductivity of the whole electrode, but also provide more active loading sites and ensure the structure stability. Moreover, the oxygen defect and N-doping in TNO could narrow the band-gap and enlarge the lattice, both improving the intrinsic electronic and ionic conductivity. The above internal & external synergistic strategies work together to accelerate reaction kinetics of N-TNO@TiC/C-NC to realize a long cycle life (up to 10000 cycles) and preeminent high-rate capability both in liquid batteries (165 mAh g−1 at 100C) and solid-state batteries (108 mAh g−1 at 40C). Furthermore, the excellent high-rate performance is also verified in TNO//LFP (LiFePO4) batteries. Our strategy provides valid routes to achieve fast reaction kinetics in LIBs for advanced high-power energy storage.