Multi-walled carbon nanotubes induced a controllable TiO2 morphology transformation for high-rate and long-life lithium-ion batteries

Abstract

We have demonstrate a facile strategy to achieve the controllable morphology transformation of TiO₂ induced by the introduction of multi-walled carbon nanotubes. The intervention of functionalized carbon nanotubes (CNTs) is key to the formation of TiO₂ nanopompons. Furthermore, the size of the obtained TiO₂ nanopompons can be controlled by modulating the CNT amounts. The obtained TiO₂ nanopompon-embedded CNT hybrid networks (TNP@CNT HNs) incorporate the advantages of hierarchical nanostructures and 3D interconnected conductive networks, including high surface area, uniform particle/pore size, short Li⁺ ion/electron transport pathway, and high electronic conductivity. These TNP@CNT HN-based anodes achieve a significant improvement in the insertion/extraction of Li⁺ ions and electrochemical performances via optimizing the CNT amounts and the size of the TiO₂ nanopompons. The lithium-ion batteries based on the optimized TNP@CNT HNs exhibit excellent cycling stability (keeping approximately 200 mA h g⁻¹ after 500 cycles at 2C rate, 1C = 170 mA g⁻¹) and rate performance (approximately 125 mA h g⁻¹ at 20C rate with a capacity retention of 77% after 2000 cycles).