Study on composite of porous Si and disordered carbon as anode materials for lithium ion batteries

Silicon and related materials have recently received considerable attention as potential anodes in Li-ion batteries for their high theoretical specific capacities. To overcome the problem of volume change, composites comprising porous silicon, disordered carbon (DC) have been prepared by pyrolyzing the critic acid. This composite anode material showed a discharge capacity of 1390 mAh/g in the first cycle, and the initial columbic efficiency is 70%. After 20 cycles, the discharge capacity of the material is 511 mAh/g. The improved stability of this material is hypothesized to depend on the unique structure of porous Si and the coated DC. The morphologies of the composites were systematically investigated by the X-ray diffraction and scanning electron microscopy. It can be observed that porous Si particles were embedded into the matrix of the DC. The capacity and cycling stability of the composites were systematically evaluated by electrochemical charge/discharge tests.