Hierarchical porous carbons derived from medicine residue for zinc ion hybrid capacitors

With the rapid development of Chinese medicine industry, the main waste (medicine residue, MR) is increasing year by year, which come from the process of Chinese medicine. Therefore, it is urgent to develop a method to utilize the residue. Herein, the N-doped hierarchical porous carbons (HPCs) were prepared from MR by the salt activation strategy. The obtained HPC presents high-specific surface area of 2730.2 m² g⁻¹, moderate N, O contents, and multi-channels for ions adsorption and transfer. Impressively, the excellent zinc ion storage properties have been gained, e.g., high capacity of 103.7 mAh g⁻¹ at 0.1 A g⁻¹, superb energy and power output of 74.07 Wh kg⁻¹ and 11.58 kW kg⁻¹, long cycle life with capacity decay of 1.16% after 10,000 cycles. This work supplies a facile route to high-value utilization of biomass waste.