Pseudocapacitive materials are used to increase the energy density of supercapacitors, but their rate performance and cycling stability are frequently unsatisfactory. Herein, we report a riboflavin-functionalized activated carbon (AC/VB2) as a negative electrode with high specific capacitance (419.1 F g⁻¹) and outstanding rate performance. The potent combination of VB2 and AC renders VB2 insoluble in alkaline liquids and fully exploits its redox characteristics. VB2 contributes additional redox reactions to AC and its reaction plateau is from −0.65 to −0.9 V (vs. Hg/HgO), favoring the storage of large amounts of energy. Based on the detailed analysis of the surface state of the material during the reaction, a strategy to improve cycling stability by controlling the charge/discharge potential window is proposed, which can effectively inhibit the desorption and overreaction of VB2, thus greatly enhancing cycling stability. The electrode can be operated stably for 100,000 cycles without any decline at high current densities. An AC/VB2(–)||LDH(+, Co-doped Ni(OH)₂) device delivered a high energy density of 58.6 Wh kg⁻¹ at a power density of 686 W kg⁻¹ and a high power density of 27,410 W kg⁻¹ at an energy density of 13.2 Wh kg⁻¹. This work offers a practical manual for making high–energy pseudocapacitive negative electrodes and enhancing their cycling stability.

赝电容材料用于提高超级电容器的能量密度，但其倍率性能和循环稳定性往往不令人满意。在此，我们报道了一种核黄素功能化活性炭（AC/VB2）作为具有高比电容（419.1 F g ^-1）和出色的速率性能。VB2 和 AC 的有效组合使 VB2 不溶于碱性液体，并充分利用其氧化还原特性。VB2 为 AC 提供额外的氧化还原反应，其反应平台为 -0.65 至 -0.9 V（相对于 Hg/HgO），有利于大量能量的存储。基于对反应过程中材料表面状态的详细分析，提出了通过控制充放电电位窗口来提高循环稳定性的策略，可以有效抑制VB2的解吸和过度反应，从而大大增强循环稳定性。该电极可在高电流密度下稳定运行10万次循环而无任何下降。AC/VB2(–)||LDH(+, 共掺杂 Ni(OH) ₂^{）装置在686 W kg -1}的功率密度下提供58.6 Wh kg ^-1的高能量密度，在13.2 Wh kg ^-1的能量密度下提供27,410 W kg ^-1的高功率密度。这项工作为制作高能赝电容负极并提高其循环稳定性提供了实用手册。