Nitrogen-doped carbon-coated Ti–Fe–O nanocomposites with enhanced reversible capacity and rate capability for high-performance lithium-ion batteries

Abstract

Rationally designed composite materials could allow each component to fully play a part in their superior performance. In this work, we designed and fabricated Ti–Fe–O nanocomposites coated with nitrogen-doped carbon to act as anode materials for lithium-ion batteries, in which Fe₃O₄ and FeTiO₃ components provide high capacity, a small fraction of TiO₂ improves cycling stability, and a nitrogen-doped carbon coating not only enhances electronic conductivity but also alleviates the agglomeration and accommodates volume change during cycling. The electrochemical performance is associated greatly with Ti/Fe molar ratio in the products, and the composite with a ratio of 1 : 2 exhibits the best cycling performance (reversible capacities of 426.4 mA h g⁻¹ at 100 mA g⁻¹ and 321.7 mA h g⁻¹ after cycling 500 times at 500 mA g⁻¹) as well as outstanding rate capabilities (374.1, 347.5, 315.9 and 260.3 mA h g⁻¹ at 200, 400, 800, and 1600 mA g⁻¹, respectively). The combined merits of its various components endow the nanocomposite with enhanced cycling and rate performance with respect to carbon-coated TiO₂ and Fe₃O₄/FeTiO₃ counterparts prepared under analogous conditions.