Multi-dimensional carbon modification strategy for lithium-ion battery anodes: Carbon-covered TiP2O7 supported by 3D carbon skeleton

Carbon coating is a beneficial method for improving surface capacitive behavior, electron transfer kinetics and cyclic stability of three-dimensional lattice lithium-embedded anode materials. Herein, we adopt one-step pyrolysis to achieve carbon-covered TiP 2 O 7 supported by a three-dimensional carbon skeleton utilizing phytic acid and glucose as carbon sources. The two-dimensional amorphous carbon layer on TiP 2 O 7 surface improves the initial Coulombic efficiency and rate capacity by inhibiting the irreversible embedding of lithium ions and reducing the interfacial charge transfer impedance. The three-dimensional carbon skeleton not only forms a conductive pathway between the carbon-covered TiP 2 O 7 , but also its large specific surface area, randomly oriented and defective carbon layer provide extra lithium storage sites and capacitive contribution. In addition, the specific capacity of the TiP 2 O 7 /C composite is still as high as 314.5 mA h g −1 after 1000 cycles at 1 A g −1 . A TiP 2 O 7 /C//LiFePO 4 full cell delivers a high energy density of 273.96 Wh kg −1 at 0.153 kW kg −1 , and retains 114.43 Wh kg −1 even at the power density of 4.086 kW kg −1 . The multi-dimensional carbon modification strategy has improved the electrochemical performance of TiP 2 O 7 -based anode materials, providing a model for synthesizing other high-performance anode materials.