Electrophoretic LiFePO4/ Graphene Composite for Li-Ion Battery Cathode Application
In the present work, we demonstrate a binder free composite electrode of LiFePO4/ graphene with ultrahigh LiFePO4 mass ratio (91.5 wt% of LiFePO4) using electrophoresis. No additional additive (other than graphene) is introduced. Enhanced capacity and improved rate performance have been demonstrated in the electrophoretic composite cathode, when compared to either the conventional one or composite cathode formed by mechanically mixing LiFePO4 and graphene. A number of key material/processing parameters have been investigated in a systematic manner in order to understand their effect on the final cathode electrochemical performance as well as identify the optimum composite cathode configuration. We also extend our discussion onto the beneficial effect of using three dimensional current collectors and the role of different ions employed during the electrophoresis process. The present methodology is simple and does not disturb the active material growth process. It can be generally applied to a variety of active material systems for both cathode and anode applications in Li-ion batteries. This work is supported by General Research Funding of the National Natural Science Foundation of China/ Research Grants Council Joint Research Scheme under project No. N_CUHK448/13.