Presentation Title: Application and Performance Improvement of Niobium Materials for Supercapacitors

Abstract: 

      Nb₂O₅-based supercapacitors offer high safety, high rate capability, and long cycle life. However, their practical application is limited by issues such as electrolyte compatibility, voltage-window imbalance, kinetic mismatch between the positive and negative electrodes, and gas generation during cycling. To address these challenges, we focused on an activated carbon//Nb₂O₅ lithium-ion capacitor system and investigated electrolyte and voltage optimization. The results show that both acetonitrile-based and carbonate-based electrolytes can cause gas generation during cycling, while acetonitrile-based electrolytes reduce impedance and improve rate performance. Elevated operating voltage further aggravated gas generation during cycling. By prelithiating the Nb₂O₅ anode and regulating the N/P ratio, the charge-transfer resistance was reduced, and Li⁺ diffusion as well as low-temperature performance were improved. The optimized device achieved a capacity retention of 87.3% at 100C/1C and retained 86.2% of its capacity after 30,000 cycles. Combined with reference-electrode potential monitoring, the high operating potential of the AC cathode was identified as the key source of gas generation. Finally, an AC-NCM//Nb₂O₅ hybrid supercapacitor was constructed, which substantially reduced gas generation compared with the lithium-ion capacitor system and enhanced energy output through cathode compositing. This work provides a basis for the design of Nb₂O₅-based supercapacitors with high power capability and long cycle life.

Biography: 

      Dr. Chongyang Yang is a Research Fellow and currently serves as Deputy Director of the Technology R&D Department at Shanghai Aowei Technology Development Co., Ltd. She has received honors including “Pearl Leading Talent” of Pudong New Area and “Pudong Craftsman.” She is engaged in the development of key materials for supercapacitors and the R&D of single cells. The supercapacitor products she developed have won the Technical Innovation Award in the Energy Storage Challenge organized by the Ministry of Industry and Information Technology for three consecutive sessions, as well as the Second Prize in the BRICS Industrial Innovation Contest. She has led four projects, including the Shanghai Sailing Program, and participated in 12 projects funded by the National Key R&D Program of China and the Science and Technology Commission of Shanghai Municipality. She has published more than 40 academic papers, been granted 15 domestic and international patents, and participated in the preparation of one industry standard.