Improving Cycling Performance of Si-Based Lithium Ion Batteries Anode with Se-Loaded Carbon Coating

Abstract

Poor cycling stability and rate capability significantly limit the commercial applications of silicon (Si) anode, due to the huge volume change and poor electronic and ionic conductivity of Si. Combining Si with SiO2 and carbon (C) can effectively improve the structural stability of electrode, but common carbon coating still suffers from the problem of comparatively low ionic conductivity. Here we designed and developed a core–shell structural Si@SiO2@C/Se anode with high ionic conductivity and structural stability by loading selenium (Se) into a carbon framework. Remarkably, it exhibits a high rate capability (612 mAh g–1 at 8 A g–1) and ultrahigh initial columbic efficiency (80.8%), which is much higher than ordinary Si/SiO2-based anode (50–60%). In addition, it shows an excellent cycling performance, which is about 1560 mAh g–1 after 150 charging/discharging cycles at the current density of 0.5 A g–1. This work provides a new technology to design high capacity alloy-type lithium-ion batteries (LIBs) anode.