Large-Scale Fabrication of Graphene-like Carbon Nanospheres for Lithium Ion Battery Application

Large scale preparation of graphene-like carbon nanospheres (GCNSs) was performed by direct-current arc discharge using C2H2 as carbon resources. The morphology and structure of the obtained products were investigated by field-emission scanning electron microscope, high-resolution transmission electron microscope, Raman spectroscope, X-ray diffraction and nitrogen adsorption. The GCNSs consist of quasi-spherically concentric graphitic shells with high purity and quality, and its size distribution is in the range of 30-50 nm. The high-quality GCNSs also exhibit highly electrical conductivity of ∼30.3 S cm−1, and can act as conductive agent to significantly improve the electrochemical performance of LiFePO4 (LFP) cathode, compared with the conventional carbon black (CB). Discharge capacity of the LFP (GCNSs) cathode reaches up to 155.6 mAh g−1 at 0.1 C, which is slightly higher than that of the LFP (CB). However, The LFP (GCNSs) cathode still delivers high capacities of 114.9 mAh g−1 and 65.2 mAh g−1 at 1 C and 10 C rates, respectively, which are much higher than those of the LFP (CB). At the same time, the discharge capacities reach up to 114.9 mAh g−1 and 80.9 mAh g−1 at 1 C and 5 C discharge rates for the first discharge, and the corresponding capacities decrease down to 108.5 mAh g−1 and 79.9 mAh g−1 after 100 cycles, respectively. This indicates excellent cyclic stability, especially at high rate charge/discharge cycles. Thus, the mass production, high crystalline and highly electrical conductivity may make the GCNSs find applications in energy conversion and storage.