Complexation-Driven Design of Ultrafine Manganese Ferrocyanide-Based Electrodes for High-Performance Supercapacitors Enabling Low-Frequency Waveform Generation

Supercapacitors are widely recognized as essential energy storage devices because of their fast-charging capability, high power output, and excellent cycle stability. These features make them highly suitable for various applications such as electric vehicles, backup power systems, and portable electronics. In this study, manganese ferrocyanide (MFC) nanoparticles were synthesized via an organic-molecule-assisted complexation method and investigated as electrode materials for advanced supercapacitors. Structural analysis confirmed a crystalline cubic structure with Mn2+ and Fe2+ ions arranged in octahedral coordination. The MFC-based electrode demonstrated pseudocapacitive behavior with a specific capacitance (SPC) of 584 F·g–1 at 5 A·g–1 in a half-cell configuration. An asymmetric supercapacitor (ASC) utilizing activated carbon as the negative electrode and MFC as the positive electrode achieved a maximum SPC of 77 F·g–1 at 1 A·g–1, with maximum energy density, EDn, of 54 Wh·kg–1 and power density, PDn, of 6.0 kW·kg–1. The device at 2 A·g–1 retained 87% of its initial SPC and maintained 90% Coulombic efficiency after 5000 continuous charge–discharge cycles, demonstrating the long-term durability of the device. The ASC was integrated into an oscillator circuit, demonstrating low-frequency waveform generation suitable for electronic circuit applications. The dual functionality highlights the potential of manganese ferrocyanide-based material for both energy storage and signal generation in low-power electronic systems.超级电容器（Supercapacitors）因其快速充电能力、高功率输出以及优异的循环稳定性，被广泛认为是不可或缺的储能器件。这些特性使其高度适用于电动汽车、备用电源系统以及便携式电子设备等诸多应用场景。本研究中，研究人员通过有机分子辅助络合法合成了亚铁氰化锰（Manganese Ferrocyanide，MFC）纳米颗粒，并将其作为先进超级电容器的电极材料开展研究。结构分析证实，该材料具有结晶立方结构，Mn²+与Fe²+离子呈八面体配位排布。该MFC基电极展现出赝电容行为，在半电池构型中，当电流密度为5 A·g⁻¹时，其比电容（Specific Capacitance，SPC）可达584 F·g⁻¹。以活性炭作为负极、MFC作为正极组装的不对称超级电容器（Asymmetric Supercapacitor，ASC），在电流密度为1 A·g⁻¹时的最大比电容可达77 F·g⁻¹，其最大能量密度（Energy Density，EDn）为54 Wh·kg⁻¹，最大功率密度（Power Density，PDn）为6.0 kW·kg⁻¹。该器件在2 A·g⁻¹的电流密度下，可保留初始比电容的87%，且在5000次连续充放电循环后仍保持90%的库仑效率（Coulombic Efficiency），展现出优异的长期循环耐久性。该不对称超级电容器被集成于振荡电路中，可产生适用于电子电路应用的低频波形。这种双重功能凸显了亚铁氰化锰基材料在低功率电子系统中同时用于储能与信号生成的应用潜力。