A free-standing electrode with hierarchical pores and graphite surface is derived from wood pellet via a catalytic graphitization. The aligned microchannels of natural wood and the high conductivity of graphite has enabled fast ionic and electronic transport. The high porosity leads to a large surface area for the deposition of redox active materials. After an electrodeposition of Ni(OH)₂ and Co(OH)₂ on the graphitized wood, the electrode exhibits a high areal capacity without significant degradation in the electrochemical performance. An asymmetric supercapacitor, with a graphitized wood as the negative electrode and a Ni(OH)₂/Co(OH)₂ deposited wood as the positive electrode, shows a high areal capacitance of 2 409 m F/cm², a high energy density of 0.75 mWh/cm² at a power density of 0.750 mW/cm². This high performance, free-standing and biodegradable wood-derived asymmetric supercapacitor demonstrates promising applications as energy storage devices.

具有分层孔隙和石墨表面的自立式电极是通过催化石墨化从木质颗粒中得到的。天然木材对齐的微通道和石墨的高电导率实现了快速的离子和电子传输。高孔隙率导致用于氧化还原活性材料沉积的大表面积。在石墨化木材上电沉积Ni（OH）₂和Co（OH）_2之后，电极显示出较高的面容量，而电化学性能没有明显降低。以石墨化木材为负极，以Ni（OH）₂ / Co（OH）₂沉积木材为正极的不对称超级电容器具有2 409 m F / cm的高面电容^{如图2所示}，在0.750mW / cm ²的功率密度下的高能量密度为0.75mWh / cm ²。这种高性能，可独立放置且可生物降解的木材衍生的不对称超级电容器证明了其作为储能设备的广阔前景。