Carbon-emcoating architecture boosts lithium storage of Nb2O5

Intercalation transition metal oxides (ITMO) have attracted great attention as lithium-ion battery negative electrodes due to high operation safety, high capacity and rapid ion intercalation. However, the intrinsic low electron conductivity plagues the lifetime and cell performance of the ITMO negative electrode. Here we design a new carbon-emcoating architecture through single CO₂ activation treatment as demonstrated by the Nb₂O₅/C nanohybrid. Triple structure engineering of the carbon-emcoating Nb₂O₅/C nanohybrid is achieved in terms of porosity, composition, and crystallographic phase. The carbon-embedding Nb₂O₅/C nanohybrids show superior cycling and rate performance compared with the conventional carbon coating, with reversible capacity of 387 mA h g⁻¹ at 0.2 C and 92% of capacity retained after 500 cycles at 1 C. Differential electrochemical mass spectrometry (DEMS) indicates that the carbon emcoated Nb₂O₅ nanohybrids present less gas evolution than commercial lithium titanate oxide during cycling. The unique carbon-emcoating technique can be universally applied to other ITMO negative electrodes to achieve high electrochemical performance.