Flexible supercapacitors (FSCs) have attracted widespread attention of many researchers as a type of portable energy storage devices. However, there are still challenges in preparing renewable and inexpensive electrode materials. Herein, we prepared the porous carbon (PC) by the two-step process involving hydrothermal method and low-temperature heat treatment using corn cob lignin as the carbon source, and different types for PC were obtained by changing the temperature of low temperature heat treatment (100 °C–300 °C). The flexible electrode film was prepared by combining the obtained corn cob lignin-based PC with reduced graphene oxide (RGO), in addition, we investigated the effect of PC obtained by different low-temperature heat treatment (100 °C, 150 °C, 200 °C, 250 °C, and 300 °C) on the electrochemical properties of the composite electrode. The optimal low-temperature heat treatment temperature (250 °C) was determined and the PC250/RGO film electrodes displayed a high area specific capacitance of 636 mF/cm2 with a mass of 2.2 mg/cm2 (specific capacitance of 289 F/g) at 0.2 mA/cm2 and 82% of the capacitance was retained after 10,000 charge and discharge cycles at 5 mA/cm2, at the same time on the electrode film flexibility test, the influence of different bending angle on the electrochemical properties can be ignored. The assembled supercapacitor had the advantages of flexible, lightweight, low price, and environment friendly, which can achieve area specific capacitance of 324.5 mF/cm2 at 0.2 mA/cm2 and 91.8% capacitance retention after 1000 charging/discharging cycles. These good electrochemical properties illustrate the application prospects of composite electrode materials in wearable and portable electronic devices.

中文翻译：

---

用于柔性超级电容器电极的玉米芯木质素基多孔碳改性还原氧化石墨烯薄膜

柔性超级电容器（FSCs）作为一种便携式储能设备引起了许多研究人员的广泛关注。然而，制备可再生且廉价的电极材料仍然存在挑战。在此，我们以玉米芯木质素为碳源，通过水热法和低温热处理两步法制备了多孔碳（PC），并通过改变低温热处理温度获得了不同类型的多孔碳(100 °C–300 °C)。通过将获得的玉米芯木质素基 PC 与还原氧化石墨烯 (RGO) 结合制备柔性电极膜，此外，我们研究了不同低温热处理（100 °C、150 °C、 200 °C、250 °C 和 300 °C) 对复合电极的电化学性能的影响。确定了最佳低温热处理温度 (250 °C)，PC250/RGO 薄膜电极显示出 636 mF/cm2 的高面积比电容，质量为 2.2 mg/cm2（比电容为 289 F/g）在 0.2 mA/cm2 和 5 mA/cm2 下 10,000 次充放电循环后仍保留 82% 的电容，同时在电极膜柔韧性测试中，不同弯曲角度对电化学性能的影响可以忽略不计。组装的超级电容器具有柔性、重量轻、价格低、环境友好等优点，在 0.2 mA/cm2 时的面积比电容为 324.5 mF/cm2，1000 次充放电循环后电容保持率为 91.8%。