Lithium-ion transfer strengthened by graphite tailings and coking coal for high-rate performance anode

Due to the anisotropy of natural graphite crystal structure, the lithium-ion transfer efficiency is poor at large current density for graphite anode. To solve this problem, the composite anode was prepared by co-pyrolysis of coking coal and graphite tailings. Results showed that the liquid plastic mass produced by coking coal pyrolysis not only realized the lamellar reconstruction of graphite tailings, but also strengthened the isotropy of the composite anode material, and the N and S heteroatoms in semi-coke strengthened the transmission of lithium ions. Compared with anode of graphite tailings (SGD), the rate capacity retention of the anode from the co-pyrolysis of oxidized graphite tailings and coking coal (OSGD-GLM) demonstrated superior rate performance (capacity retention increased from 13.98% to 32.00% at current density of 5.0 A g−1compared to 0.1 A g−1), long-term stability and excellent full cell rate performance. More importantly, the lithium-ion diffusion coefficient of OSGD-GLM under charging state was measured by galvanostatic intermittent titration (GITT), which was in the range between 6.26 × 10−10 and 1.71 × 10−8 cm2 s−1, significantly higher than that of commercial graphite anode.