Carbon decorated Li-based orthosilicate electrode for energy storage application

To address the rising energy demand, high energy, power, capacity, and broad electrochemical potential window of electrode material is necessary. In this report, we successfully prepared Li₂FeSiO₄ electrode material via a low-temperature hydrothermal method for fulfilling dual applications in Li-ion batteries and supercapacitors. The prepared material has been passed via relevant characterization techniques like X-ray diffraction, FTIR, FESEM, and electrochemical (CV, EIS, and GCD). The optimized carbon-coated LFS-3 (Li₂FeSiO₄/AC_x x = 1 wt %) delivered the best electrochemical performances with a higher charge capacity (200 mAh g⁻¹) and discharge capacity (182 mAh g⁻¹). LFS-3 also delivered a low charge transfer resistance (R_ct) of 2.5 Ω, resulting in an improved D_Li⁺ of 5.0 × 10^–13 cm² S⁻¹ in Li-ion battery testing. The supercapacitor testing of optimized LFS-3 delivered a specific capacitance of 64 F g⁻¹ @ 0.15 A g⁻¹ and R_ct of 1 Ω. LFS-3 supercapacitor retained an excellent capacity of 89% and 70% coulombic efficiency after 3000 cycles. The energy density of 8.85 Wh kg⁻¹ and power density of 75 W kg⁻¹ were obtained for the LFS-3 supercapacitor at 0.15 A g⁻¹. The LFS-3 supercapacitor illuminated the red LED for 15 min and a panel comprising 26 LEDs for 12 min. A charge storage mechanism has also been proposed for LFS/AC-type supercapacitors. The outcome illustrates that LFS/AC has enough potential to fit as an innovative electrode material for high-energy storage applications.