Synergy of a hierarchical porous morphology and anionic defects of nanosized Li4Ti5O12 toward a high-rate and large-capacity lithium-ion battery

Exploring electrode materials with a high volumetric energy density and high rate capability remains of a great challenge for nanosized-Li4TiSO12 (LTO) batteries. Here, hierarchical porous Ti3+C N Br co doped LTO (LTOCPB-CC) is synthesized using carboxyl-grafted nanocarbon (CC) and cetylpyridinium bromide (CPB) as combined structure-directing agents. Ti-4(+)-O-CPB/LitCC is designed as a new molecular chelate, in which CPB and CC promote the uniform mixing of Li+ and Ti4+ and control the morphology of TiO2 and the final product. The defects (oxygen vacancies and ion dopants) formed during the annealing process increase the electron/hole concentration and reduce the band gap, both of which enhance the n-type electron modification of LTO. As-prepared LTOCPB-CC has a large specific surface area and high tap density, as well as a high electronic conductivity (2.84 x 10(-4) S cm(-1)) and ionic conductivity (3.82 x 10(-)(12) cm(2) s(-1)), which are responsible for its excellent rate capability (157.7 mA h g(-1) at 20 C) and stable long-term cycling performance (0.008% fade per cycle after 1000 cycles at 20 C). (C) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.