ИСТИНА

Sodium-ion batteries (SIBs) can be a possible alternative to lithium-ion batteries (LIBs) due to sodium availability and low cost. Commercialization of SIBs requires electrode materials with high specific capacity, good cycling stability, low cost and low toxicity. Hard carbon (HC) is one of the promising negative electrode material in NIBs, since HC demonstrates a high capacity in contrast to graphite [1]. Hard carbon (HC) is a non-graphitizable form of carbon material, which consist of curved graphitic domains and micropores. There are a variety of methods to synthesize hard carbon, where template synthesis aims an increase the specific capacity of hard carbon through increasing the number of inner micropores. This approach helps to obtain HCs with extremely high specific capacity up to 480 mAh/g [2]. Porous SiO2 is an attractive material for use as a nanoscale template because its porosity and average pore diameter can be easily adjusted [3]. This work is devoted to SiO2-template synthesis of hard carbon. At first, the mixture of glucose and tetraethoxysilane (TEOS) as a source of SiO2 was pretreated in hydrothermal condition. The template was removed by hydrofluoric acid, and then the material was subjected to annealing at 1300 oC. The concentration of hydrofluoric acid was varied in order to achieve formation of maximum number of micropores instead of silicon dioxide. Influence of synthetic conditions, morphology on electrochemical performance was studied. Obtained SiO2-templated HC demonstrated high specific discharge capacity of 372 mAh/g.