Spherical graphite produced from waste semi-coke with enhanced properties as an anode material for Li-ion batteries

“Turning waste into treasure” is of significance on the sustainable development in nowadays. The semi-coke in fine particles, abandoned as solid waste, has less commercial value in metallurgical industry and also causes environment contamination. Considering this, the man-made graphite is prepared by a facile graphitization of the semi-coke using silicon as catalyzer at 2300 °C. The obtained sample reveals an interesting microstructure with special spheres and a high degree of graphitization with smaller specific surface area. Furthermore, taken as anode material for lithium ion batteries, the sample displays excellent lithium storage properties, which delivers a high delithiation capacity of 347.06 mA h g-1 at 0.05C, even the capacity can maintain 162.3 mA h g-1 at 3C. More surprising is that the capacity retention can attain the 97.7% at 0.5C after 700 cycles. Comparing to the tradition anode materials, the SG obtained can be served as anode materials in consideration of predominant advantages: (i) raw materials at a lower cost; (ii) lower charge/discharge plateau voltage after graphitization at 2300 °C; (iii) ultra-rate performance and excellent cycle retention at higher rate; (iiii) the unique nucleation mechanism make the sample with the sphere structure. Also, one-step heat treatment is easier to conduct and handle. As a result, the graphite would become a competitive candidate for application in large scale in anode materials of lithium-ion batteries.