Biomass-derived carbon coated SiO2 nanotubes as superior anode for lithium-ion batteries

Silica (SiO2) is regarded as a promising anode for lithium-ion batteries due to the high specific capacity, abundant resources and low cost. However, the inherently poor electrical conductivity and the huge volume variation during charge/discharge process significantly hinder the application of SiO2. Designing nanostructured SiO2 and coating with high conductivity materials are effective methods to solve the above challenges. In this work, advanced SiO2 anodes were prepared by coating hollow SiO2 nanotubes (SNTs) with lignin or phenolated and depolymerized lignin furfural resin (PDLF)-derived carbon. The novel structure of the obtained SNTs greatly promotes the rapid transport for both Li+ and electron, increases the exposed active sites for Li+ insertion and accommodates the volume change of SNTs. Especially, PDLF possesses abundant functional groups, high carbon content and thermosetting property, which are beneficial to the dispersion of SNTs and formation of a cross-linked 3D conductive network. Thereby, SNTs@C-PDLF presents higher specific capacity of 661 mAh g(-1) at 100 mA g(-1), superior rate capability (262 mAh g(-1) at 3000 mA g(-1)) and better cycling stability (549 mAh g(-1) at 1000 mA g(-1) after 800 cycles) compared with SNTs@C-lignin and pristine SNTs.