Accelerating Charge Transfer in Supercapacitor Electrodes through Built-In Electric Fields
Xiaofeng Zhang, Z. WANG, Muhammad Sufyan Javed, Qian Zhang, Zilin Gong, Yue Pei, Gao Qian, Mengling Zhao, Yingqi Li, Kui‐Qing Peng, Weihua Han
Abstract
The commercial development of supercapacitors (SCs) heavily depends on a stable electrochemical performance with a long life span. However, insufficient charge transfer within the SC electrodes is a major challenge. This paper introduces an interface engineering strategy to enhance charge transfer by creating a built-in electric field (BIEF) at the interface of MXene electrode material. Ti 3 C 2 T x MXene decorated with Ti 2 N nanocubes was selected as the electrode material, and a stable BIEF was formed at the Ti 2 N/Ti 3 C 2 T x interface due to the different surface potentials of Ti 2 N and Ti 3 C 2 T x . Our results show that the designed Ti 2 N/Ti 3 C 2 T x electrode exhibits a high capacitance of 250.3 F g –1, an excellent rate capability of 63.6% at 20 A g –1, and an outstanding cycling stability of 95.8% at 10 A g –1 after 10,000 cycles in a three-electrode system. The assembled two-electrode device with activated carbon (AC) as the anode, the Ti 2 N/Ti 3 C 2 T x //AC, demonstrates an excellent energy storage performance, with an energy density of up to 50.8 Wh kg –1 and an outstanding cycling stability of 96.77% over 10,000 cycles. The improved energy storage performance and cycling stability are attributed to the accelerated ion transportation and adsorption/desorption on the electrode surface, driven by the electric field force generated by the BIEF. In addition, the in-situ growth of Ti 2 N on the Ti 3 C 2 T x surface is conducive to improving the structural stability of the electrode material and promoting the stable existence of the BIEF. This work provides a new pathway for developing ultrastable and high-performance SCs.