Tuning the Defects of Two-Dimensional Layered Carbon/TiO(2) Superlattice Composite for a Fast Lithium-Ion Storage

Defect engineering is one of the effective ways to improve the electrochemical property of electrode materials for lithium-ion batteries (LIB). Herein, an organic functional molecule of p-phenylenediamine is embedded into two-dimensional (2D) layered TiO(2) as the electrode for LIB. Then, the 2D carbon/TiO(2) composites with the tuning defects are prepared by precise control of the polymerization and carbothermal atmospheres. Low valence titanium in metal oxide and nitrogen-doped carbon nanosheets can be obtained in the carbon/TiO(2) composite under a carbonization treatment atmosphere of N(2)/H(2) gas, which can not only increase the electronic conductivity of the material but also provide sufficient electrochemical active sites, thus producing an excellent rate capability and long-term cycle stability. The prepared composite can provide a high capacity of 396.0 mAh g(−1) at a current density of 0.1 A g(−1) with a high capacitive capacity ratio. Moreover, a high specific capacity of 80.0 mAh g(−1) with retention rate of 85% remains after 10,000 cycles at 3.0 A g(−1) as well as the Coulomb efficiency close to 100%. The good rate-capability and cycle-sustainability of the layered materials are ascribed to the increase of conductivity, the lithium-ion transport channel, and interfacial capacitance due to the multi-defect sites in the layered composite.