介孔/微孔复合材料的控制制备与储能应用

The microstructure design, controllable synthesis and electrochemical energy storage performance of mesoporous/microporous composites are investigated. The mesoporous/microporous aerogels, metal organic framework (MOF) materials, ordered mesoporous/microporous materials, layered structured oxides are synthesized using template-inducing and self assembling routes. Based on the hierarchically mesoporous/microporous microstructure characteristics of ordered mesoporous materials, aerogels, MOF, layered structured oxide materials, the strategies including doping, surface fictionalization, cooperative coupling and combination, are adopted to obtain a high efficiency in electrochemical energy conversion and storage for lithium ion battery, lithium-sulfur battery and super-capacitors. Active materials with adjustably content, size, chemical species, dispersivity, are modified and combined in the mesoporous/microporous carbon matrix, to fully realize the cooperative effect in energy storage and conversion of the mesoporous/microporous composite electrodes. Redox chemical reaction process and lithiation/delithiation process taken place at the interface between electrode and electrolyte are investigated, the electrochemical performance including storage capacity, cycle stability, rate capability of m mesoporous/microporous composite electrodes are studied using electrochemical impedance spectroscopy, galvanostatical charge–discharge, and cyclic voltammetry techniques. The influence of cooperative effects, surface and interface effects between the micropores and mesopores, additive active materials and matrix materials on the electrochemical storage performance and the capacity fading mechanism of the mesoporous/microporous composite electrodes are investigated. The mechanism and theoretical model of energy storage and conversion for the mesoporous/microporous composite electrodes are set up. The relation between the capacity, cycle stability, rate capability and the chemical composition, microstructure, hierarchically porous characteristic is investigated. Lithium battery and super-capacitor based on hierarchically mesoporous/microporous composite electrodes with high storage capacity, superior rate capability and cycle stability are developed.

以介孔/微孔复合材料的储能应用为目标，实现对凝胶、金属有机骨架化合物（MOF）、有序介孔、层状结构氧化物等介孔/微孔电极材料的设计与可控制备。基于有序介孔、凝胶、MOF、层状结构氧化物等丰富的介孔与微孔结构特征，依据高效能量转换与储存（锂离子电池、锂硫电池、超级电容器）的性能需求，采用掺杂、功能化、协同复合等措施，实现不同功能的活性物质在分级孔内的组分、尺寸、含量、分散度的控制，发挥微孔与介孔的协同作用。分析电极界面发生的电化学过程与离子嵌入和脱出机制，探讨相关的容量衰减机制及改善循环稳定性和倍率性能的措施,分析介孔与微孔结构间的协同机制、表界面效应等对能量转换与储存的影响规律。建立介孔/微孔复合电极的高效能量储存的机制与理论模型。探究容量、循环稳定性、倍率性能与介孔/微孔电极的化学组分、微观结构、孔结构等的关系本质，研制高容量、倍率性能佳、长寿命的分级多孔复合电极的锂电池与超级电容器。

本项目围绕电化学储能国家重大战略需求，以分级孔材料微纳结构的设计和制备为基础，深入探究材料微观结构与界面作用机制、复合材料组分协同作用，电极界面反应动力学、中间相催化/转化过程、载流子电极界面传输行为与储能机理的关联规律，研发了一系列高倍率、长循环寿命的金属离子电池以及高能量密度的锂硫电池、锂氧电池。具体研究成果如下：. 设计合成一系列孔径可调、维度有序的介孔/微孔材料，包括MOFs衍生孔材料、有序孔材料、三维凝胶以及三维MXene材料。揭示了微孔活性基元优化荷质储运动力学过程的内在规律，阐明了分级孔结构空间限域和应力缓冲的重要作用。其中，有序介孔结构的ZnCo2O4锂离子电池负极材料，2 A g-1电流密度下比容量高达1623 mAh g-1。. 提出系统性的分级孔材料电极反应动力学优化策略。通过表面官能团调控原位构筑高比能复合材料，实现了高容量活性颗粒的均匀负载和快速荷质传输。揭示了缺陷活性中心提升二次电池动力学性能机理及储能机制，典型工作包括：利用非金属元素梯度掺杂构筑蕴含内建电场的MOF衍生异质结构；开发“挥发-扩散-再捕获”制备Co单原子材料的策略；合成制备富含晶界和边缘缺陷的Ti3C2 MXene量子点团簇，局域电荷重排大幅提升锂氧电池双功能催化活性。阐明了自组装MXene基分子异质结优化荷质输运的一般性规律，界面耦合作用有效抑制了二维MXene材料的自堆叠效应，同时实现了电子/离子在界面处的快速传导。. 开展了高比能二次电池正极中间相催化/转化动力学及负极生长沉积动力学研究。揭示了催化剂改性-吸附能优化-中间产物催化转化之间的内在关联，提出基于表面改性、缺陷工程和异质结工程促进多硫化锂吸附转化、过氧化锂形核长大的普适性策略，实现锂硫电池2 A g-1下稳定循环2000圈，锂氧电池1 A g-1下12800 mAh g−1 的超高比容量和0.75 V的低极化电位；对金属负极进行表面改性，设计了莲藕式三维中空碳纤维结构的Li/C复合电极，合成三维沉积基体和金属氟化物界面层，抑制枝晶生长并显著提高二次电池循环稳定性。