Tang Yongfu, Li Haiwei, Zhang Ruonan, Guo Wenfeng, Yu Meiqi
Hebei Key Laboratory of Applied Chemistry, School of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004, P. R. China.
ACS Omega. 2021 Oct 20;6(43):28528-28537. doi: 10.1021/acsomega.1c02271. eCollection 2021 Nov 2.
Metal-organic framework (MOF)-derived carbon materials were widely reported as the anodes of lithium-ion capacitors (LICs). However, tunning the structure and electrochemical performance of the MOF-derived carbon materials is still challenging. Herein, metal carbide materials of CoZnC@NC-8:2 were obtained by the pyrolysis of the MOF materials of CoZnZIF-8 (Zn/Co ratio of 8:2). A half-cell assembled with the CoZnC@NC-8:2 electrode exhibits a discharge capacity of the electrode material of 598 mAh g at a current density of 0.1 A g. After 100 cycles, the retention rate of discharge specific capacity is about 90%. The high performance of CoZnC@NC-8:2 is ascribed to its high crystalline degree and well-defined structure, which facilitates the intercalation/deintercalation of lithium ions and buffers the volume change during the charge/discharge process. The high capacitance contribution ratio calculated by cyclic voltammetry (CV) curves at different scanning rates indicates the pseudocapacitance storage mechanism. LICs constructed from the CoZnC@NC-8:2 material have a rectangular CV curve, while the charge-discharge curve has a symmetrical triangular shape. This study indicates that MOF-derived carbon is one of the promising materials for high-performance LICs.
金属有机框架（MOF）衍生的碳材料作为锂离子电容器（LIC）的阳极被广泛报道。然而，调节MOF衍生碳材料的结构和电化学性能仍然具有挑战性。在此，通过热解CoZnZIF-8（锌/钴比例为8:2）的MOF材料获得了CoZnC@NC-8:2的金属碳化物材料。用CoZnC@NC-8:2电极组装的半电池在电流密度为0.1 A g时，电极材料的放电容量为598 mAh g。100次循环后，放电比容量的保留率约为90%。CoZnC@NC-8:2的高性能归因于其高结晶度和明确的结构，这有利于锂离子的嵌入/脱嵌，并缓冲充放电过程中的体积变化。通过不同扫描速率下的循环伏安（CV）曲线计算得到的高电容贡献率表明了赝电容存储机制。由CoZnC@NC-8:2材料构建的LIC具有矩形CV曲线，而充放电曲线具有对称三角形形状。这项研究表明，MOF衍生碳是用于高性能LIC的有前途的材料之一。
