赝电容负极材料储能电位区间调控及其在多级三维导电碳基底上的原位生长

It is an effective approach to design high performance charge storage device through improving cyclic stability and power density for asymmetric pseudocapacitor which has high energy density due to its high working voltage and high capacitance. We found in our previous work that the high potential limit of negative pseudocapacitive electrode material had significant influence on the cyclic stability of the assembled asymmetric pseudocapacitor. Motivated by this, we will try to control the charge storage potential window of negative pseudocapacitive electrode materials to adapt its high potential limit with the low potential limit of positive electrode materials. Thereafter the cyclic stability of the assembled asymmetric pseudocapacitors can be significantly improved through the guarantee that both of the electrodes can work in their safe potential range, whilst the high working voltage, and then the high energy density of the capacitor, can be ensured by the low enough potential limit of the negative electrode. The power density of the pseudocapacitor will be improved through nanostructure fabrication for the pseudocapacitive materials on three dimensional hierarchical carbon substrates to establish high electron and ion transportation avenues. Valence-Optimization will be conducted for transition metal oxides like MoOx, WOx and VOx to control their charge storage potential window. Negative pseudocapacitive materials with large charge storage potential window will also be designed through syntheses of hybrids/composites of self-doped polypyrrole with inorganic pseudocapacitive materials, as well as inorganic pseudocapacitive composites syntheses. This work is aimed to explore high performance negative pseudocapacitive materials for asymmetric pseudocapacitor with high energy density, high power density and long cycling stability.

组装具有高工作电压和高电容的非对称赝电容器，可有效提高超级电容器能量密度。解决赝电容器循环稳定性和功率密度问题，保持超级电容器优势，是制备高性能储能器件的有效途径。针对我们在前期工作中发现的赝电容负极储能电位上限对电容器循环稳定性有重要影响问题，本申请提出借合理设计MoOx、WOx、VOx等氧化物价态组合调控其储能电位区间，进行自掺杂聚吡咯与储能电位范围适当的无机赝电容材料复合/杂化、及无机赝电容材料复合研究，以扩展负极储能电位上下限。在保证负极储能电位下限进而保证电容器高工作电压的基础上，合理扩展其储能电位上限，以与正极储能电位下限有效衔接，保证两极在各自安全电位范围内工作，进而提高赝电容器循环稳定性。并在多级三维导电碳基底上构建赝电容负极材料纳米结构，建立电子和离子传导的快速通道，提高电极功率性能和储能贡献，为具备高能量密度、高功率密度、高循环稳定性的超级电容器提供高性能赝电容负极。

在部分剥离石墨箔电极上的石墨烯片层表面、碳布上交错编织的碳纤维表面，进行吡咯或苯胺的电化学聚合，生长聚吡咯纳米线阵列/相互交织纳米线，或聚苯胺纳米棒阵列/纳米线。进行碳化处理，形成碳纳米线/纳米棒阵列，或相互交织的碳纳米线/碳纳米网，构建多级导电碳基底。研究碳化温度，碳化气氛等因素对构建导电碳基底的影响。进行功能化处理，为后续赝电容材料均匀生长及建立与基底之间的相互作用创造条件。在多种三维碳基底上生长了在负电位区间具有电化学活性的氧化钼、氧化钒、氧化铁、钨青铜、钼的聚阴离子化合物等，构建无机赝电容负极。研究了氧化还原电对、电解液组成等因素与储能电位区间的关系，及对电化学性能的影响，在此基础上设计了氧化还原电对调控、电解液设计等策略，调控了电极的储能电位上下限，扩展了储能电位区间。在三维碳基底上进行了氧化钼、氧化钨分别与聚吡咯、聚苯胺的电化学复合，和在聚吡咯中引入具有电化学活性的掺杂钼多酸阴离子、磷钼多酸阴离子，构建无机-有机复合赝电容负极；在三维碳基底上生长了VOx@MoO3、V5O12/VO2、Fe2O3/Fe3O4、Fe3O4/FeOOH异质结构，构建无机复合赝电容负极。通过综合利用各组分在不同电位区间的电化学活性、诱导协同效应等措施，实现电极在大电位范围内具有高电化学性能。在三维碳基底上生长了大载量氧化锰，构建了几种高性能正极。合理匹配正负极储能电位范围，组装了高电压超级电容器，为构建具备高能量密度、高功率密度、高循环稳定性的超级电容器进行了有益探索。根据项目研究成果发表了致谢本项目资助的SCI论文30篇，另有1篇已通过审稿人初审，正在修改中。其中15篇发表在SCI影响因子大于10的期刊上，包括Adv. Eng. Mater.（IF 25.245）1篇、ACS Energy Lett.（IF 19.003）1篇、Adv. Funct. Mater.（IF 16.836）2篇（另有1篇已通过审稿人初审，正在修改中）、Nano Energy（IF 16.602）1篇、ACS Nano（IF 14.588）1篇、Small（IF 11.459）1篇、J. Mater. Chem. A（IF 11.301）4篇、Che. Eng. J.（IF 10.652）4篇。发表在ACS Nano和Small上的2篇论文入选ESI高被引论文。