PVP-assisted Self-assembling of lacelike TiP2O7 encapsulated in carbon bracket for advanced Lithium-ion storage

One fundamental issue for developing high-performance lithium-ion batteries (LIBs) locates in the exploration of stable anode materials that can provide stable channels and sufficient active sites for Li-ion shuttling. Polyanionic Pyrophosphate-based materials (e.g., TiP2O7) have been considered as the anode materials due to their advantages in ion migration kinetics and cycle stability. However, the large bandgap and strong P-O covalent bond in TiP2O7 result in inferior electron conductivity, limiting its Li-ion storage capability. Herein, a novel lacelike TiP2O7 submicro-spheres with bracket C compounds (TiP2O7@C) were synthesized with PVP-oriented aggregation using one-step hydrothermal and heat treatment method. The pyrolytic carbon coating layer prominently optimizes the electron transfer kinetics, avoids the erosion of organic electrolytes, and stabilizes the hierarchical structure in the ultralong cycle processes. When served as the anode materials for LIBs, the prepared TiP2O7@C composite showed an excellent reversible Li-ion storage capacity of 411.7 mAh g(-1) after 700 cycles under a high current density of 1.0 A g(-1). The kinetic analysis and pseudocapacitance calculation demonstrated that the tailored structure promotes the electrochemical capability. This proposed strategy displays significant performance benefits, offering a novel pathway to modify the morphology and electron/ion transfer of polyanionic anode materials for LIBs.

Automated summary

The exploration of stable anode materials is a fundamental issue for developing high-performance lithium-ion batteries. In this study, a novel lacelike TiP2O7 submicro-spheres with bracket C compounds (TiP2O7@C) were synthesized, which demonstrated excellent reversible Li-ion storage capacity and optimized electron transfer kinetics.