I tried to dissolve in HCL, HNO3 separately and mixture of both with DI Water (HCL:HNO3:H2O=10:10:80 by volume) but LiFePO4 did not dissolve. I also mixed solution by magnetic stirrer overnight still black particles are seen in the solution. I assumed those black particles were carbon, so I removed coating from H2O2 but still did not succeed. Please help me with proper procedure.