Graded porous carbon (HPC) is a potential ideal material for the preparation of supercapacitors due to its high specific surface area, excellent pore structure and good conductivity. However, the specific capacitance of HPC alone is not ideal, and the energy storage capacity is poor, which is difficult to meet the energy storage needs of supercapacitors. By combining the HPC doped pseudo-capacitive materials, the composites can achieve better electrochemical properties, such as high cycle stability, high power and energy density, through the synergistic effect of EDLC and pseudo-capacitance mechanisms. Therefore, developing a direct, flexible, and environmentally friendly method to construct biomass-based N,P co-doped HPCs in a controlled manner to achieve a rational polar surface and excellent pore structure is extremely attractive, but still a great challenge.
Lu Qilin's team from Minjiang University used chitosan as the carbon skeleton and phytic acid as the molecular bridge, pore-forming agent, activator and phosphorus source to construct a carbon aerogel doped with nitrogen and phosphorus through the strategy of "in-situ co-doping/self-regulating activation". The resulting nitrogen and phosphorus co-doped hierarchical porous carbon exhibits high specific capacitance, excellent rate capability and electrochemical stability, and can be assembled together with its hydrogel precursor to form flexible supercapacitors with excellent performance. It was found that NPC carbon aerogels could achieve a well-developed interconnected porous framework, high specific surface area (1494.8 m2 g-1), extremely high heteroatom doping content (12.67% N, 2.21% P) and high defective graphite structure (AD/AG=2.45) at a low carbonization temperature (600 °C) and a short carbonization time (60 min). Under the three-electrode system, NPC carbon aerogel has a high specific capacitance of 449 F g-1 at a current density of 1 A g-1 and 282 F g-1 at a current density of 50 A g-1, and has excellent rate capability and excellent electrochemical stability. The capacitance characteristics and ion transfer characteristics of NPC were further evaluated, and the slow kinetic process of NPC-600-5 was as high as 29.7% at 1 mV s-1, and its solution resistance (Rs) and charge transfer resistance (Rct) were 0.21 Ω and 0.07 Ω, respectively, showing ultrafast ion transfer ability. In addition, the quasi-solid-state flexible supercapacitors assembled based on NPC//CPPC//NPC have excellent energy storage capacity of 27.06 Wh kg-1, a wide operating temperature range (-20°C-60°C), remarkable cycling stability, and superior foldability. The results were recently published in the International Journal of Biological under the title "Chitosan-based high-performance flexible supercapacitor via "in-situ co-doping/self-regulation-activation" strategy Macromolecules. The first author of the paper is Wang Hanchen, a master's student, and the corresponding author is Associate Professor Lu Qilin. The research was supported by the National Natural Science Foundation of China (32301529), the Fuzhou Science and Technology Major Project (2023-ZD-007), the Fujian Provincial Key Laboratory of Green Technology for Ecological Industry Open Fund (WYKF-EIGT2023-4), and the Young Talent Training Program of Minjiang University. Illustrated reading
Fig.1 Synthesis mechanism of NPHPC and schematic diagram of the construction of flexible supercapacitors
图2 (a) NPC-500-5、(b) NPC-600-5、(c) NPC-700-5、(d) NPC-800-5 (e) NPC-600-0、(f) NPC-600-3、(g) NPC-600-7的SEM图像。 (h) NPC-600-5的SEM-EDS mapping图像
Fig.3 Electrochemical performance of NPCs
Fig.4 Electrochemical kinetic analysis of NPC-600-5
Fig.5 Performance analysis of flexible supercapacitorsCorresponding author's profile: Lu Qilin, associate professor of Minjiang University, distinguished professor of "Mindu Scholars", high-level talent in Fujian Province. He is mainly engaged in the research of renewable fiber low-carbon materials, including biomass-based nanomaterials, nanogenerators and wearable devices, flexible sensors, functional textile materials, etc., and has presided over the National Natural Science Foundation of China, the key project of scientific and technological innovation in Fujian Province, the first class of the China Postdoctoral Science Foundation, the Natural Science Foundation of Fujian Province, and more than ten major science and technology projects in Fuzhou City, and participated in the "13th Five-Year Plan" national key research and development projects. As the first/corresponding author, he has published more than 30 papers in international SCI journals such as Nano Energy, Carbohydrate Polymers, ACS Sustainable Chemistry & Engineering, International Journal of Biological Macromolecules, etc., and authorized 27 invention patents.
--Testing Services--
Paper Links:
https://doi.org/10.1016/j.ijbiomac.2024.133346 Source: Frontiers of Polymer Science