Green synthesis of N, O, P co-doped porous carbon from co-pyrolysis of bamboo and ammonium polyphosphate for supercapacitors

Pyrolysis of recycled biomass waste to produce carbon materials for application in electrochemical energy storage can be characterized as both environmentally friendly and high value-added. In this paper, porous carbon materials were synthesised using a two-step pyrolysis method with moso bamboo as the raw material, ammonium polyphosphate (APP) as the green dopant, and potassium bicarbonate as the activator, and successfully applied to supercapacitors.The maximum weight loss peak of APP appeared around 300℃, coinciding with the thermal decomposition process of bamboo. The carbon material (AB21) obtained at a lower first-step pyrolysis temperature (300℃) and APP doping ratio (2:1) had the best electrochemical performance, with a specific capacity of 347 F/g at 1 A/g and 284 F/g at 20 A/g, and capacity retention of up to 81.84%. AB21 featured a specific surface area of 1143 m2/g and total N and P content of 1.48% and 0.22%, respectively. Available in a Calla Lily-like porous structure, AB21 possessed electrochemical performance superior to that of the comparison group, which had a larger specific surface area. The symmetric supercapacitor assembled had an energy density of 14.71 Wh/kg at a power density of 150 W/kg. The exceptional electrochemical performance of this carbon material highlights the potential for converting biomass waste into high-value carbon materials for efficient electrical energy storage.