context: For full cells, commercial lithium iron phosphate (LFP) was used as the cathode material. A mixture of LFP powder, acetylene black (conductive additive) and polyvinylidene fluoride (PVDF) with a mass ratio of 8:1:1 in N-methyl-2-pyrrolidone (NMP) was first coated on aluminum foil, dried in a vacuum oven at 80 °C overnight and used as the LFP cathode. The areal mass loading of LFP was around 5 mg cm−2. The charge–discharge voltage was recorded from 2.0 to 4.0 V while the current rate varied from 0.2 to 2.0C (1C is equals to 170.0 mA h g−1). Electrochemical impedance spectroscopy (EIS) measurements were performed on an IVIUM electrochemical workstation with a frequency range of 105–0.01 Hz.
answer:  lithium iron phosphate (LFP)