Sodium titanium fluorophosphate (NaTiPO4F) is a phosphate-based material known for its stable crystal structure, good ionic conductivity, and redox-active properties, making it a promising battery-type electrode. In order to enhance the capacitive performance, NaTiPO4F was combined with manganese dioxide (MnO2), well known pseudocapacitive material, via co-precipitation method in three different ratios (50:50,70:30, 80:20). The XRD analysis of NaTiPO4F/MnO2 revealed the crystalline nature and agglomerated granular clusters were observed from FESEM. The crystal reflections obtained from the HRTEM-SAED pattern matched with XRD results. From BET studies, surface area and average pore size of all the nanomaterials were calculated. The average particle size value of NaTiPO4F/MnO2 was obtained from DLS. XPS measurements undertaken before and after cyclic stability studies reflected no change in the surface oxidation states of the elements present in the composite electrode. Further, the electrochemical characteristics of the fabricated NaTiPO4F/MnO2 electrode at different compositional ratios (50:50, 70:30 and 80:20) were studied in three electrode cell assembly using alkaline (1 M KOH) electrolyte. From CV studies, the optimized NaTiPO4F/MnO2 (50:50) electrode exhibited the maximum specific capacitance of 620 Fg−1 at a scan rate of 10 mVs−1. From GCD studies, the optimized electrode displayed the maximum specific capacitance of 564 Fg−1 (current density: 3 Ag−1) with 77.5% capacitive retention after 5000 charge/discharge cycles. Furthermore, the fabricated asymmetric NaTiPO4F/MnO2 //AC device demostrated the highest energy density of 21 Whkg−1 (power density: 1050 Wkg−1, current density: 3 Ag−1) and highest power density of 6989 Wkg−1 (energy density: 3.306 Whkg−1, current density: 20 Ag−1) with capacitive retention of 66.67% (15 Ag−1) and Coulombic efficiency of 85.74% after 5000 charge/discharge cycles. The synergy between the battery-type NaTiPO4F and the pseudocapacitive MnO2 contributed to the improved electrochemical performance, suggestive of the enormous potential of NaTiPO4F/MnO2 (50:50) electrode for next-generation energy storage applications.

Electrochemical investigation of binary NaTiPO₄F/MnO₂ as an advanced supercapacitor electrode

期刊论文
发表日期：

2025年11月9日

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Sredha MB,
Julie Charles

摘要

Sodium titanium fluorophosphate (NaTiPO₄F) is a phosphate-based material known for its stable crystal structure, good ionic conductivity, and redox-active properties, making it a promising battery-type electrode. In order to enhance the capacitive performance, NaTiPO₄F was combined with manganese dioxide (MnO₂), well known pseudocapacitive material, via co-precipitation method in three different ratios (50:50,70:30, 80:20). The XRD analysis of NaTiPO₄F/MnO₂ revealed the crystalline nature and agglomerated granular clusters were observed from FESEM. The crystal reflections obtained from the HRTEM-SAED pattern matched with XRD results. From BET studies, surface area and average pore size of all the nanomaterials were calculated. The average particle size value of NaTiPO₄F/MnO₂ was obtained from DLS. XPS measurements undertaken before and after cyclic stability studies reflected no change in the surface oxidation states of the elements present in the composite electrode. Further, the electrochemical characteristics of the fabricated NaTiPO₄F/MnO₂ electrode at different compositional ratios (50:50, 70:30 and 80:20) were studied in three electrode cell assembly using alkaline (1 M KOH) electrolyte. From CV studies, the optimized NaTiPO₄F/MnO₂ (50:50) electrode exhibited the maximum specific capacitance of 620 Fg⁻¹ at a scan rate of 10 mVs⁻¹. From GCD studies, the optimized electrode displayed the maximum specific capacitance of 564 Fg⁻¹ (current density: 3 Ag⁻¹) with 77.5% capacitive retention after 5000 charge/discharge cycles. Furthermore, the fabricated asymmetric NaTiPO₄F/MnO₂ //AC device demostrated the highest energy density of 21 Whkg⁻¹ (power density: 1050 Wkg⁻¹, current density: 3 Ag⁻¹) and highest power density of 6989 Wkg⁻¹ (energy density: 3.306 Whkg⁻¹, current density: 20 Ag⁻¹) with capacitive retention of 66.67% (15 Ag⁻¹) and Coulombic efficiency of 85.74% after 5000 charge/discharge cycles. The synergy between the battery-type NaTiPO₄F and the pseudocapacitive MnO₂ contributed to the improved electrochemical performance, suggestive of the enormous potential of NaTiPO₄F/MnO₂ (50:50) electrode for next-generation energy storage applications.