Interfacial engineering of polyhedral carbon@hollowed carbon@SiO2 nanobox with tunable structure for enhanced lithium ion battery

Abstract

In this work, the polyhedral carbon@hollowed carbon@SiO2 (PC@HC@SiO2) nanocubes are designed by employing the ZIF-8 as template for high-performance lithium-ion batteries (LIBs) anode. The nanostructures of ZIF-8@SiO2 can be tunneled by controlling the hydrolysis durations of TEOS. As a result, the PC@HC@SiO2 composite is obtained by a subsequent high temperature carbonization treatment on ZIF-8@SiO2. When used as anode for LIBs, it exhibits high initial discharge capacity of 863.6 mAh g−1 with Coulombic efficiency of 85% at the current density of 0.1 A g−1. Further, the reversible capacity stabilizes at 723 mAh g−1 after 150 cycles. Even the current density is increased to 1.0 A g−1, a highly reversible capacity of 321.2 mAh g−1 can be enabled after 800 cycles, demonstrating the superior rate and long cycling capability. Remarkably, the density functional theory calculation realizes that the lithium storage capacity of PC@HC@SiO2 is significantly enhanced by the strong interfacial interaction between the HC and the SiO2. Besides, the novel nanostructure of PC@HC@SiO2 not only promotes the kinetics for lithiation/de-lithiation and diffusion process, but also relieves the volume expansion, leading to high anode performance.