Design high performance biomass-derived renewable carbon material for electric energy storage system

Improving the utilization efficiency of waste biomass resources and industrial electric energy is the key research direction in the clean energy field. Here, rhododendron petals with extensive resources and low cost were used as precursors, the nitrogen-doped derived renewable carbon prepared by simple processing technology demonstrates its feasibility and application value in electrical energy storage systems. For the potassium-ion batteries anode, the renewable carbon delivers superior electrochemical properties: the initial reversible capacity has 294.7 mAh/g, and the retention rate after 150 cycles is 83.5%. Even at the high rate of 2000 mA/g, it still maintains 72.4% after a long cycle. In addition, the energy storage mechanism of the material was verified by different characterization methods: the high potential slope area corresponds to the adsorption behavior of potassium-ion on the surface active sites, and the low potential plateau area shows the characteristics of potassium-ion inserted into graphitic layers. The increased active functional groups and expanded graphitic layer spacing are important factors for the excellent cycle performance and rate capacity of the renewable carbon. These design and application methods have provided strategic guidance and new development directions for reusing biomass waste resources.