Nitrogen-rich carbon/SiO2 nanotubes composites prepared by self-assembly as high-performance anode lithium-ion battery

Abstract

Silicon dioxide (SiO2) has huge reserves and relatively high theoretical specific capacity (1965 mAh g−1) on the earth, so it is recognized by many researchers as one of the anode materials for the next generation lithium-ion battery (LIBs). However, compared with commercial graphite materials, silicon-based anode materials are severely limited in wide application because of their poor conductivity, low lithium-ion (Li+) diffusivity and huge volume effect, which lead to obvious capacity attenuation and poor rate performance. Herein, we developed a simple method to prepare silica nanotubes (SNTs) by sol-gel method with Cetrimonium Bromide-Disodium edetate dihydrate (CTAB-EDTA) template. SNTs were modified by 3-aminopropyltriethoxysilane (APTES) to form SNTs with amino groups (SNTs-NH2). The SiO2 tubes were coated with N−doped carbon layer by self-assembly of amino carboxyl groups of tartaric acid, melamine and SNTs-NH2. The unique hollow tubular structure can maintain the stability of the structure and interface to a certain extent during the lithium/de-lithium process, thus improving the cycle stability of the electrode. In addition, N-doped carbon layer can not only improve the electron migration rate, but also contribute to the storage and transfer of Li+. Compared with the original SNTs, N−doped carbon-coated SNTs (NC@SNTs) has a reversible capacity of 972 mAh g−1 after 100 cycles at a current density of 0.1 A g−1, a cycle stability capacity of 634 mAh g−1 after 500 cycles at a current density of 1 A g−1. Therefore, the unique template and self-assembly process can prepare anode composites with excellent properties. It is of great significance to the large-scale production and commercial application of silicon−based anode LIBs in the future.