OP45C-encapsulated T-Nb2O5nanocrystals for high performance Li-and Na-ion batteries

This contribution [1] presents an effective route, based on a two-step process to synthesise carbon-encapsulated metal oxide nanocrystals (NCs). The first step consists of the solvothermal reaction of a metal precursor with acetophenone to simultaneously produce metal oxide NCs and an organic carbon precursor homogeneously coating their surface, thus limiting their growth and preventing their agglomeration. The second step consists in the heat treatment to increase the crystallinity degree of the metal oxide NCs and carbonize the organic carbon precursor.The case of carbon-encapsulated orthorhombic niobium oxide (T-Nb2O5/C) NCs is here considered as an example and it is shown that the C content and size of the T-Nb2O5NCs can be controlled, while the morphology of the T-Nb2O5/C nanostructures produced can be varied via the addition of assembly promoting agents. This enables tuning and optimization of their properties, as demonstrated by utilizing the produced T-Nb2O5/C nanocomposites as active anode materials in Li-and Na-ion batteries.The nanomaterials prepared under optimized conditions exhibit excellent high rate performance, delivering a specific capacity of ~90 mAh/g at 100 C rate in a Li-ion electrolyte and ~125 mAh/g at 20 C rate in a Na-ion electrolyte [1].-