Cheng Kun-Peng, Gu Ren-Jie, Wen Li-Xiong
Research Center of the Ministry of Education for High Gravity Engineering and Technology, Beijing University of Chemical Technology Beijing 100029 China
College of Chemical Engineering, Beijing University of Chemical Technology Beijing 100029 China.
RSC Adv. 2020 Mar 24;10(20):11681-11693. doi: 10.1039/d0ra01411g. eCollection 2020 Mar 19.
A clustered countercurrent-flow micro-channel reactor (C-CFMCR) with adjustable magnification times was constructed for the preparation of KMnF perovskite fluoride by a co-precipitation process, in which the concentrations and feed rates of reactants were precisely controlled. Benefitting from the enhanced micromixing efficiency of the microreactor, the KMnF particles prepared in C-CFMCR were smaller and less aggregated than those produced with traditional stirred reactors (STR). The prepared KMnF was applied as the electrode material in supercapacitors, and the electrochemical measurements showed that the KMnF obtained under optimal conditions had a discharge specific capacitance of ∼442 F g at a current density of 1 A g, with a decline of ∼5.4% after 5000 charge-discharge cycles in an aqueous electrolyte of 2 M KOH. It was also found that the morphologies and electrochemical performances of the prepared KMnF particles changed accordingly with the micromixing efficiencies of C-CFMCR, which can be adjusted by the reactor structure and operating conditions. An asymmetric supercapacitor assembled with the KMnF and activated carbon exhibited an energy density of 13.1 W h kg at a power density of 386.3 W kg, with eminent capacitance retention of ∼81.2% after 5000 cycles. In addition, only a slight amplification effect of C-CFMCR on the co-precipitation process was noticed, indicating that the C-CFMCR is a promising technology for the massive and controllable production of KMnF particles as well as other ultrafine particles.
构建了一种具有可调放大倍数的簇状逆流微通道反应器（C-CFMCR），用于通过共沉淀法制备钙钛矿氟化物KMnF，其中反应物的浓度和进料速率得到精确控制。受益于微反应器增强的微混合效率，在C-CFMCR中制备的KMnF颗粒比传统搅拌反应器（STR）生产的颗粒更小且团聚更少。将制备的KMnF用作超级电容器的电极材料，电化学测量表明，在最佳条件下获得的KMnF在1 A g的电流密度下具有约442 F g的放电比电容，在2 M KOH水性电解质中进行5000次充放电循环后下降约5.4%。还发现，制备的KMnF颗粒的形貌和电化学性能随C-CFMCR的微混合效率而相应变化，这可以通过反应器结构和操作条件进行调节。用KMnF和活性炭组装的不对称超级电容器在386.3 W kg的功率密度下表现出13.1 W h kg的能量密度，在5000次循环后具有约81.2%的出色电容保持率。此外，仅观察到C-CFMCR对共沉淀过程有轻微的放大作用，这表明C-CFMCR是大规模可控生产KMnF颗粒以及其他超细颗粒的有前途的技术。
