Strawberry straw-derived hierarchical porous carbon with naturally aligned channels for high performance supercapacitors

The development of renewable energy storage technologies has become a critical priority for global sustainable development and energy diversification. In this study, strawberry straw, an agricultural waste material, was converted into porous carbon through KOH activation. In this structure, the innate vascular channels was preserved to create pathways for rapid ion transport, while the concurrent chemical etching generates a multitude of macro/meso/micropores, resulting in an integrated multi-scale pore network. At an optimized KOH/C ratio of 3:1, the as-prepared SPC₃ sample attained an ultrahigh specific surface area of 2746.5 m² g^-1. The preserved vascular bundle channels provide efficient pathways for ion transport, while the high specific surface area offers substantial active sites for charge storage. This synergy resulted in a high specific capacitance of 277 F g^-1 at 1 A g^-1 and exceptional cycling stability (95.6% of its capacitance after 10,000 cycles at 10 A g^-1). When assembled into a symmetric supercapacitor, the SPC_3//SPC₃ device delivered an energy density of 20.9 Wh kg^-1 at a power density of 600 W kg^-1, maintaining 16.83 Wh kg^-1 even at 6000 W kg^-1, highlighting its great potential for high-power energy storage applications.