One-step synthesis of Nb-doped TiO2 rod@Nb2O5 nanosheet core–shell heterostructures for stable high-performance lithium-ion batteries

Abstract

One of the main drawbacks with applying the most promising electrode materials in lithium-ion batteries is their intrinsic poor electronic conductivity. Many approaches which include mixing them with good electrical conductors have been developed to solve this problem, yet they do not improve the lattice electronic conductivity within the crystal. Here we present a one-step hydrothermal route for fabricating the core–shell heterostructures through sequential growth of the core and shell materials. The cores are Nb-doped TiO₂ rods with improved conductivity that can deliver high capacity, yet the Nb₂O₅ nanosheets shells can act as a protective layer to prevent electrode dissolution and maintain the electrode integrity over long term cycles and contribute additional lithium storage capacity. When employed as an anode material in lithium-ion batteries, it exhibits an outstanding cycle stability of 189 mA h g⁻¹ at 170 mA g⁻¹ for more than 700 cycles. This work provides an important strategy to improve the conductivity of the host and construct a protective layer by simply adding a guest ion in reaction.