（急）FeO@C/MAX复合材料的制备及电化学动力学研究

Preparation and electrochemical kinetics of FeO@C/MAX composites

摘要:

以α-Fe2O3@C作为碳源，与钛粉和铝粉一同进行高温煅烧，制备FeO@C/MAX复合材料(FCM)。采用XRD、SEM等表征了不同Ti/C比、Al/C比制备的FCM的结构、组成及形貌变化，通过电化学测试进行动力学分析，定量计算FCM的赝电容占比，并推测出FCM可能的电荷储存机理。结果表明，随着Ti/C比以及Al/C比增加，FCM中MAX相(Al2Ti4C2-Ti3AlC2混合物)的含量增加，且α-Fe2O3转变为不稳定的FeO。根据电化学测试，当Ti、Al、C的摩尔比为3:1:2时，在10mV/s扫速下FCM的比电容最大为168.37F/g，约为α-Fe2O3的8倍。动力学分析表明，FCM中存在的MAX相在电化学中发生氧化还原反应，为粒子的快速电子输运提供了条件，增加了FCM赝电容的占比，其中FCM-312在10mV/s的扫速下赝电容占比为22.12%。

Abstract:

The α-Fe2O3@C is used as a carbon source and is calcined at high temperature with titanium and aluminum powders to form FeO@C/MAX (noted as FCM). The FCM charge storage mechanism is explored by kinetic analysis to quantify the pseudocapacitance percentage of the FCM. The compositional and morphological changes of FCM at different Ti/C ratios and Al/C ratios were investigated by characterization with XRD and SEM. The results show that the content of the MAX phase (Al2Ti4C2-Ti3AlC2 mixture) in the FCM product increases with increasing Ti/C ratio as well as Al/C ratio, and that α-Fe2O3 transforms into unstable FeO. According to electrochemical tests, when the molar ratio of Ti, Al and C is 3:1:2, the maximum specific capacitance of FCM is 168.37 F/g at a sweep rate of 10 mV/s, which is approximately 8 times higher than that of α-Fe2O3. Through kinetic analysis, it was found that the MAX phase present in FCM undergoes redox reactions in electrochemistry, providing conditions for rapid electron transport of particles, adding the proportion of FCM pseudocapacitors. The results show that the pseudocapacitance of the FCM-312 is 22.12% at a sweep rate of 10mV/s.