Vesicular porous carbon with outstanding electrochemical performances in Zn-based devices: Extracted from asphalt and wood precursors

Asphalt has emerged as one of the outstanding precursors of porous carbon in electrochemical electrodes, e.g., supercapacitors, zinc ion capacitors (ZICs), and zinc iodine batteries (ZIOBs). However, the chemical reactivity of asphalt precursors is a concern due to their conjugated character. Fortunately, biomass, with its high volatile content and abundance of O-groups, is well-appropriate for modifying the more chemically inert asphalt. Accordingly, based on the previous one-step oxidation activation, the porous carbons have been obtained by wood-modified petroleum asphalt (PA) and with the support of KHC₂O₄-KBr molten salts. The typical sample, PA/SAC modified by sandalwood (SA), possesses a high specific surface area (1339.1 m² g⁻¹), a unique vesicular structure, abundant defects, and multiple heteroatoms, showing excellent electrochemical properties. In the three-electrode system, PA/SAC possesses a high specific capacitance of 431.2 F g⁻¹ (0.5 A g⁻¹). Next, as a ZIC cathode, a high capacity of 234.9 mAh g⁻¹ and a high energy density of 187.9 Wh kg⁻¹ can also be achieved. More importantly, the complex PA/SAC@I obtained by mixing PA/SAC with iodine also achieved a high capacity of 273.0 mAh g⁻¹ in the cathode of ZIOB. In conclusion, this work accomplishes the utilization of cheap asphalt and biomass while inspiring the electrochemical energy storage business.