Bamboo-based self-supporting electrodes via green activation for high-performance supercapacitors

As a potential high-efficiency energy storage device, supercapacitor electrode materials encounter persistent challenges, including limitations in energy density and stability, particularly at large loadings. In this work, a bamboo-based self-supporting thick electrode (∼30 mg cm−2) is prepared. The electrode takes full advantage of the vertical growth channels and surface oxygen-containing functional groups of bamboo, which improves the ion transport kinetics within its structure. Inspired by the fermentation process of bread with baking soda, the electrode material is prepared by KHCO3 activation at 1000 °C. The optimal sample exhibits a specific surface area of 903 m2 g−1 and an electrode specific capacitance of 142.7 F g−1 at current density of 1 A g−1. Furthermore, the assembled supercapacitor device exhibits excellent electrochemical performance even at high loadings. Specifically, the supercapacitor exhibits high energy density of 20.36 Wh kg−1 at 400 W kg−1. The device also has excellent cycling stability with a capacitance retention of 104.4 % after 10,000 cycles at a high current of 5 A g−1. Benefiting from the green preparation process, high energy density, and excellent cycling stability, the bamboo-based self-supporting thick electrode exhibits immense potential for further development and utilization.