Enhanced performance of porous carbon microspheres from bamboo fiber for supercapacitors through acid-assisted hydrothermal carbonization

Porous carbon microspheres with a regular spherical shape were prepared from bamboo pulp fiber through the hydrothermal carbonization process with the assistance of hydrochloric acid and phosphoric acid. It was observed that a higher concentration of hydrochloric acid resulted in increased yields of carbon microspheres with porous surfaces compared to phosphoric acid, and the specific surface area was reached 923.9 m2/g after Na2CO3 activation. The resulting PCS-Cl-0.1 electrode exhibits a high specific capacitance of 292.8F/g at 0.2 A/g and excellent rate performance. This work demonstrates the effectiveness of acid-assisted hydrothermal carbonization in controlling the morphology and enhancing the electrochemical performance of carbon microspheres.