Structural and electrochemical properties of LiFePO₄ cathode synthesized by solid-state reaction using FeC₂O₄.2H₂O precursor from local Indonesian ilmenite mineral

Producing LiFePO₄ cathode materials using precursors processed from local resources has been our goal. LiFePO₄ has been synthesized by surfactant-assisted solid-state reaction method using local FeC₂O₄.2H₂O precursor as a result from chemical precipitation process of Indonesian ilmenite processing waste (LFP Local). As a comparison, LiFePO₄ was also synthesized by the same method using commercial FeC₂O₄.2H₂O precursor (LFPC). The XRD, SEM–EDS, and TEM showed that LFP Local had a perfect crystallinity structure and small particle size. EIS measurement showed that LFP Local and LFPC had charge transfer resistance of ~ 111.35 \(\Omega\) $\mathrm{\Omega }$ and ~ 31.52 Ω, respectively. The Li-ion diffusion coefficient of LFP Local and LFPC was calculated and determined to be 1.419 × 10⁻⁹ cm² S⁻¹ and 5.221 × 10⁻¹⁰ cm² S⁻¹, respectively. The charge–discharge test showed that the highest specific capacity values for LFP Local and LFPC were 147 mAh g⁻¹ at 0.1 C and 118 mAh g⁻¹ at 0.1 C, respectively. However, LFP Local showed lower specific capacity stability than LFPC, which might be due to the less homogeneous particle size and smaller crystalize size, as shown by TEM and XRD data. On the other hand, the charge transfer reversibility is lower indicated by potential peak-to-peak separation, as detected in the cyclic voltammetry test. Our result suggests that local Indonesian ilmenite mineral can be used as a raw material of FeC₂O₄.2H₂O precursors for LiFePO₄ cathodes of high-performance lithium-ion batteries.