Facile synthesis of Nb2O5/carbon nanocomposites as advanced anode materials for lithium-ion batteries

Nb2O5 has attracted increasing attention as anode materials for lithium ion batteries (LIBs) because of its high safety and good structural stability. However, its electrochemical properties are controlled by the poor electronic conductivity and low ion diffusivity. In this work, we report the preparation of Nb2O5/carbon nanocomposites overcomes these issues by a facile solvothermal method with subsequent calcination. The Nb2O5 nanoparticles are homogeneously distributed in a carbon matrix derived from carbon quantum dots. As anode materials for lithium ion batteries, the as-prepared Nb2O5/carbon nanocomposites exhibit high capacity, good rate capability and cyclic stability. The Nb2O5/carbon nanocomposites can deliver a stable capacity of 385 mA h g−1 after 100 cycles at 0.1 A g−1. A specific capacity of 240 mA h g−1 is maintained even after 600 cycles at 1 A g−1. The composite electrode exhibits improved electrochemical performance than pure Nb2O5 electrode. With the homogeneous distribution of the Nb2O5 in a carbon matrix derived from carbon quantum dots, the aggregation of Nb2O5 during cycles can be prevented and the electronic conductivity of Nb2O5 can be enhanced.