Surface functionalized 3D carbon fiber boosts the lithium storage behaviour of transition metal oxide nanowires via strong electronic interaction and tunable adsorption energy

Abstract

The Li-ion storage properties of transition metal oxide (TMOs) electrodes such as Li-ion intercalation-based electrodes are usually enhanced by hybridizing with 3D carbon scaffolds. However, understanding of the large variation in performance enhancement is rarely reported. As a proof of concept, intercalation reaction-based TMO (V₂O₅ and TiO₂) nanowires were hybridized with two types of 3D carbon scaffolds (namely pristine carbon fiber cloth, CFC and porous N-doped CFC, PNCFC). Theoretical calculation predicts that the PNCFC@TMO hybrids displayed reasonably lower adsorption energy towards easier Li-ion intercalation than those of CFC@TMOs. Electrochemical properties further disclosed that PNCFC-based hybrids exhibit the best lithium storage performance. Furthermore, in situ Raman, XPS and charge redistribution studies not only decipher that strong electronic interaction exists between PNCFC and TMOs but also consistently affirm that such interaction is ascribed to the shift of the p-adsorption energy, facilitating rapid kinetics and leading to improved Li storage properties.