基于氧化石墨烯/导电聚合物的钒液流电池活性材料的研究

Vanadium redox flow battery (VRFB) is a new type of device for energy storage and conversion. The electrode materials of VRFB are mainly focused on the graphite felt, carbon fiber and other materials. However, these materials were proved to show poor kinetic reversibility for the positive and the negative redox couples without further treatment, as well as low area and inefficient active sites for catalytic redox reaction, leading to an unsatisfactory power density, energy efficiency and voltage efficiency. Graphene oxide (GO) has quasi-two-dimensional layered structure attached with a large number of oxygen containing group, and relatively high specific surface area. GO shows greatly enhanced electro-catalytic activity towards the positive and negative redox couples in VRFB, but its electronic conductivity is poor. In order to further improve the performance of the electrode process kinetics, thereby improving the power density and energy efficiency of the VRFB, the mixed conduction (ion and electron) mechanism is proposed by designing and building micro-nano hybrid materials based on GO in this study. The GO with high specific surface area is well assembled with conductive polymer. The material-device-performance related dynamic feedback mechanism is built through the assembly of VRFB system. The micro-mechanism of electron transfer and ion diffusion and reaction in electrode-electrolyte interface is also investigated.

钒液流储能电池是一种高效电能储存和转换装置，对其电极材料的研究主要集中在石墨毡、炭纤维等材料，但这些材料的催化氧化还原面积低、活性位少，正负极电对氧化还原可逆性差，从而造成电池能量效率和功率密度低下。氧化石墨烯是一种含氧官能团丰富的二维纳米材料，其比表面积较高，对钒液流电池正负极区氧化还原电对显示出了较好电化学催化作用，但其电子导电性有待进一步提高。为进一步提高材料的电极过程动力学性能，进而改善钒液流电池能量效率和功率性能，本研究提出基于“混合传输”（电子和离子）机制，将具有良好催化活性的高比表面积氧化石墨烯与导电性聚合物有效复合，构筑氧化石墨烯基微纳结构复合电极材料，改善提高液流电池能量效率和功率性能，揭示电子转移与离子在电极-电解液界面扩散与反应的微观作用机制，建立材料-器件-性能关联动态反馈机制。

钒液流储能电池是一种高效电能储存和转换装置，对其电极材料的研究主要集中在石墨毡、炭纤维等材料，但这些材料的催化氧化还原面积低、活性位少，正负极电对氧化还原可逆性差，从而造成电池能量效率和功率密度低下。氧化石墨烯是一种含氧官能团丰富的二维纳米材料，其比表面积较高，对钒液流电池正负极区氧化还原电对显示出了较好电化学催化作用，但其电子导电性有待进一步提高。. 为进一步提高材料的电极过程动力学性能，进而改善钒液流电池能量效率和功率性能，本研究首先采用电化学沉积方法在氧化石墨烯表面沉积了一层具有良好导电性的聚苯胺材料，在用于钒液流电池正负极活性材料时，氧化石墨烯/聚苯胺复合材料具有的良好的导电性、丰富的含氧官能团，大大改善了对正极VO2+/VO2+和负极V2+/V3+电对的催化氧化还原性能，反应阻抗大大降低。. 对中间相炭微球进行氧化处理后，得到了表面具有类氧化石墨烯片层组成的孔道结构和丰富含氧官能团的炭材料，采用电化学沉积方法在其表面沉积了一层具有良好导电性的聚苯胺材料。在用于钒液流电池正负极活性材料时，氧化中间相炭微球/聚苯胺复合材料具有的良好的导电性、丰富的含氧官能团和孔道结构，揭示了电子转移与离子在电极-电解液界面扩散与反应的微观作用机制。