A ternary B, N, P-Doped carbon material with suppressed water splitting activity for high-energy aqueous supercapacitors - Carbon4Energy

Porous carbon materials (PCMs) have been extensively investigated as electrode materials for supercapacitors, yet are severely hindered by low capacitance and energy density. Herein, we reported the efficient synthesis of a ternary B, N, P-doped PCMs (termed as BNP-C) via polymer dehalogenation strategy. The atomic contents of B, N, and P, as characterized by XPS, are 11.5, 1.1, and 0.8 %, respectively, yet intriguingly resulting in limited water splitting activity due to the overwhelmingly presented B dopant. This specific feature can be taken advantage of for effectively expanding the workable voltage window while maintaining large capacitances of aqueous supercapacitors (ASCs). Besides, the BNP-C exhibited porous 3D structure, hierarchical porous structure, and large surface area of 1118.5 m2 g-1, which simultaneously ensured the BNP-C-assembled ASC with superior capacitive performance. As confirmed by both Dunn and Trasatti methods, pseudocapacitance remarkably contributed ~44.9 and ~40.2 % respectively in overall capacitances for the BNP-C, which was mainly credited to the heavy decoration of B. In addition, the BNP-C symmetric ASC delivered very good long-term stability and high specific energy of 12.0 and 10.9 Wh kg-1 in acidic and alkaline electrolytes, respectively.