High specific capacity of carbon coating lemon-like SiO2 hollow spheres for lithium-ion batteries

Abstract

Hollow structure is a kind of special structure that can effectively relieve the volume expansion of anode material, but the large space in hollow structure also sacrifices the specific capacity of the material to some extent. In this paper, lemon-like hollow SiO2 spheres were prepared by soft template method as anode material for lithium-ion batteries. The advantages of the anode material are: (1) There is a certain space inside the hollow sphere to relieve the volume expansion, which can improve the cyclic stability of the material; (2) There are many SiO2/SiOx nanoparticles wrapped inside the hollow sphere, which can improve the specific capacity of the material in the cycle; (3) There is a certain gap between the SiO2/SiOx nanoparticles inside the hollow sphere. This provides a channel for the migration of Li+ in the cycle, which is conducive to the migration of Li+ and improves the rate performance of lithium-ion battery. (4) The lemon-like hollow SiO2 spheres can be prepared by one-step method, and the preparation process is simple. The discharge mass specific capacity of composite materials is 786 mA h g−1 at current density of 1.0 A g−1 after 500 cycles. The discharge specific capacity at current densities of 0.2, 0.5, 1.0, 2.0 and 5.0 A g−1 are 900, 854, 787, 681, 492 mA h g−1, respectively. The composite materials show certain potential as anode materials for high performance lithium-ion batteries.