Tang Yongbing, a researcher of the Functional Thin Film Materials Research Center of the Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, and his team, together with Li Zhensheng, a professor at the City University of Hong Kong, successfully developed a highly nitrogen-doped porous microcrystalline carbon nanomaterial that exhibits high capacity as a negative electrode for potassium ion batteries And long cycle characteristics. Related research results "Ultrahigh Nitrogen Doping of Carbon Nanosheets for High Capacity and Long Cycling Potassium Ion Storage" Advanced Energy Materials ").
Due to the characteristics of the standard hydrogen electrode potential (-2.93 V), which is rich in potassium reserves and close to lithium, potassium-based energy storage devices have good application prospects in the field of large-scale energy storage. However, due to the large ionic radius of potassium ions (1.38 Angstroms), it not only hinders its insertion / extraction in the electrode material, the kinetics are slow, but it also causes a large volume change in the electrode material, making the cycle stability more stable difference. Therefore, there is an urgent need to develop efficient and low-cost electrode active materials for potassium ion storage.
Based on the above considerations, Tang Yongbing and his team members Chang Xingqi, Zhou Xiaolong, Ou Xuewu and others have successfully developed highly nitrogen-doped porous microcrystalline carbon nanomaterials, whose porous structure is conducive to the rapid diffusion of potassium ions and contains a large amount of micro Crystal carbon nanosheets are beneficial for the intercalation and adsorption of potassium ions. Studies have shown that the electrochemical reaction of this high-nitrogen-doped microcrystalline carbon nanomaterial is a synergistic mechanism of the diffusion reaction and the pseudocapacitance reaction. As a potassium negative electrode, it has a high capacity of ~ 410 mAh / g, and is at 5Ag-1. The capacity retention rate after 3000 cycles of reversible cycling at high current density is about 70%. This work provides a new strategy for designing high-performance potassium electric anode materials.