Influence of carbon layer thickness on the Li-ion storage property of [002]-oriented β-Li2TiO3@C nanowires

Abstract

Monoclinic Li2TiO3 (β-Li2TiO3) is a kind of potential candidate for anodic material of high-safety lithium-ion batteries (LIBs) for its stable zero-strain layered structure; however, β-Li2TiO3 has intermediate Li+ ​ion conductivity and low electronic conductivity, affecting its practical application. Herein, [002]-oriented β-Li2TiO3@C nanowires have been synthesized via a convenient low-temperature solid state method. The diffusion of Li+ ​along the ab plane of β-Li2TiO3 has relatively low energy barrier, and the obtained [002]-oriented nanowires (with diameter of 50–70 ​nm) provide short and accessible Li+ ​diffusion pathways along the ab plane. In addition, the modification of carbon layers with optimal thickness (∼8 ​nm) can promote the Li+ transfer kinetics and improve the electronic conductivity. As a result, [002]-oriented β-Li2TiO3@C nanowires exhibit excellent electrochemical performance, involving high specific capacity (243.1 mAh g−1 at 50 ​mA ​g−1), high rate capability (173.6 and 155.3 mAh g−1 at current rates of 50 and 200 ​mA ​g−1), and good cyclic stability (160.9 mAh g−1 at 50 ​mA ​g−1 after 100 cycles). Therefore, [002]-oriented β-Li2TiO3@C nanowires have the potential to be used as anodic material for high-performance LIBs. This work could provide inspiration to improve the Li-ion storage property of anodic materials by purposely tailoring the structure and crystal orientation.