Development of supercapacitors with high energy density and long cycle life using sustainable materials for next-generation applications is of paramount importance. The ongoing challenge is to elevate the energy density of supercapacitors on par with batteries, while upholding the power and cyclability. In addition, attaining such superior performance with green and sustainable bio-mass derived compounds is very crucial to address the rising environmental concerns. Herein, we demonstrate the use of watermelon rind, a bio-waste from watermelons, towards high energy, and ultra-stable high temperature green supercapacitors with a high-voltage ionic liquid electrolyte. Supercapacitors assembled with ultra-high surface area, hierarchically porous carbon exhibits a remarkable performance both at room temperature and at high temperature (60 °C) with maximum energy densities of ∼174 Wh kg⁻¹ (25 °C), and 177 Wh kg⁻¹ (60 °C) – based on active mass of both electrodes. Furthermore, an ultra-high specific power of ∼20 kW kg⁻¹ along with an ultra-stable cycling performance with 90% retention over 150,000 cycles has been achieved even at 60 °C, outperforming supercapacitors assembled with other carbon based materials. These results demonstrate the potential to develop high-performing, green energy storage devices using eco-friendly materials for next generation electric vehicles and other advanced energy storage systems.

对于下一代应用，使用可持续材料开发具有高能量密度和长循环寿命的超级电容器至关重要。当前的挑战是在保持功率和可循环性的同时，将超级电容器的能量密度提高到与电池相同的水平。此外，用绿色和可持续的生物质衍生化合物获得如此优异的性能对于解决日益严重的环境问题至关重要。在本文中，我们演示了西瓜皮的使用，西瓜皮是一种来自西瓜的生物废料，可用于高能，具有高压离子液体电解质的超稳定高温绿色超级电容器。具有超高表面积的超级电容器，^-1（25°C）和177 Wh kg ^-1（60°C）–基于两个电极的有效质量。此外，即使在60°C的温度下，也能达到约20 kW kg ^-1的超高比功率，以及在150,000次循环中具有90％保持率的超稳定循环性能，其性能优于与其他碳基材料组装的超级电容器。这些结果证明了使用环保材料为下一代电动汽车和其他先进储能系统开发高性能，绿色储能设备的潜力。