Superior performance of ordered macroporous TiNb2O7 anodes for lithium ion batteries: Understanding from the structural and pseudocapacitive insights on achieving high rate capability

Abstract

Titanium niobium oxide (TiNb2O7) has been regarded as a promising anode material for high-rate lithium ion batteries (LIBs) due to its potential to operate at high rates with improved safety and high theoretical capacity of 387mAhg−1. Herein, three-dimensionally ordered macroporous (3DOM) TiNb2O7 composed of interconnected single-crystalline nanoparticles was prepared using polystyrene (PS) colloidal crystals as a hard template. The final product yields a homogeneous, continuous, and effective honeycomb-like construction. This architecture provides facile Li+ insertion/extraction and fast electron transfer pathway, enabling high-performance lithium ion pseudocapacitive behavior, leading to good electrochemical performance. As a result, the 3DOM-TiNb2O7 shows a remarkable rate capability (120mAhg−1 at 50C) and durable long-term cyclability (82% capacity retention over 1000 cycles at 10C). The work presented herein holds great promise for future design of material structure, and demonstrates the great potential of TiNb2O7 as a practical high-rate anode material for LIBs.