Banana peels, a common fruit waste was adopted as a material precursor in this study to synthesize highly porous activated carbon from banana peels (ABP) which serves as an electrode material for a symmetric supercapacitor device. The activation was done using KOH pellets at different carbonization temperatures ranging from 750 °C to 950 °C. The ABP sample obtained from the 900 °C carbonization temperature (ABP900) exhibited unique material properties such as hierarchical porous nano-architecture containing micropores, and mesopores with the highest specific surface area (1362 m² g⁻¹). Electrochemical performance investigation in different neutral aqueous electrolytes showed that the best response was obtained in NaNO₃ for the ABP900 electrode. The symmetric device subsequently assembled using 1 M NaNO₃ operated in a potential window of 1.8 V, exhibited a specific capacitance of 165 F g⁻¹ with a corresponding energy density of 18.6 W h kg⁻¹ at 0.5 A g⁻¹. A 100% capacitance retention and columbic efficiency were obtained after 10000 continuous charge-discharge cycles at 5 A g⁻¹. Remarkably, after subjecting the symmetric device to a voltage holding test for 60 h, the specific capacitance was observed to increase from 165 F g⁻¹ to 328 F g⁻¹ with a corresponding increased energy density to about 36.9 W h kg⁻¹ at 0.5 A g⁻¹, suggesting a 98% increase in device energy density from its initial value after voltage holding. Thus, the results reported showcase the ABP900 material as a potential nanostructured porous material useful in the design of high-performance electrodes for stable electrochemical capacitors.

香蕉皮，一种常见的水果废料，被用作本研究的材料前体，是从香蕉皮（ABP）合成高度多孔的活性炭，而香蕉皮用作对称超级电容器装置的电极材料。使用KOH颗粒在750°C至950°C的不同碳化温度下进行活化。从900°C的碳化温度（ABP900）获得的ABP样品表现出独特的材料特性，例如包含微孔的分层多孔纳米结构以及具有最高比表面积（1362 m ²  g ^-1）的中孔。在不同中性水性电解质中的电化学性能研究表明，在NaNO _3中获得了最佳响应用于ABP900电极。对称设备随后使用1M的NaNO组装₃在1.8 V的电位窗口操作时，表现出165 F G的特定电容^-1与18.6 W时千克的相应的能量密度^-1 0.5 A G ^-1。在5 A g ^-1下进行10000次连续充放电循环后，可获得100％的电容保持率和库仑效率。值得注意的是，在对对称器件进行了60 h的电压保持测试后，观察到比电容从165 F g ^-1增加到328 F g ^-1，同时能量密度相应增加到36.9 W h kg ^-1。 0.5 A g ^-1，表明器件的能量密度从保持电压后的初始值增加了98％。因此，报道的结果展示了ABP900材料是一种潜在的纳米结构多孔材料，可用于设计稳定电化学电容器的高性能电极。