考虑到能源危机和日益增长的环境问题，开发高安全性、低成本、低污染、储能性能突出的可充电储能设备成为实际应用中备受关注的问题。目前，锂离子电池是最早研究的可充电储能设备，因其高能量密度的优势，广泛应用于人类实际生活中。然而，由于锂的资源有限和成本较高，使用水系电解液的水溶液金属离子电池被认为是锂离子电池的很有前途的替代装置。在这些水系电池中，水系锌离子电池由于环境友好性、更高的安全性和较低的成本这些优势，在未来的实际应用中拥有更高的应用潜力。本论文的研究目的旨在提高MXene基正极复合材料的快速动力学和长循环稳定性，深入研究电化学性能和储锌机理，主要研究内容如下：

      (1) 利用范德华自组装方法在V₂O₅纳米板表面设计了Ti₃C₂T_x MXene层，以抑制电化学过程中的钒的溶解，从而大大提高锌离子的存储性能。正极表面的MXene层保持了结构完整性，抑制了钒溶解；V₂O₅和MXene之间的异质界面改善了宿主的电化学动力学；由于复合材料中的润滑水分子，导致宿主层之间的静电排斥力减少，促进了界面Zn²⁺扩散。因此，复合材料在电流密度500 mA g^-1下表现出初始放电容量为345.1 mAh g^-1，并且显示了超过5000次循环的长期循环稳定性。

     (2) 基于上一章的研究，针对Ti₃C₂T_x MXene属于惰性成分，不能提供容量的贡献问题，而具有电化学活性的V₂CT_x MXene有显著的导电性，对V₂O₅/V₂CT_x MXene复合材料进行弱氧化处理作为正极。弱氧化策略下，使V₂CT_x转化为衍生物V₂O_x@V₂CT_x，V-C-V键的保留使得原始MXene导电性被保留；弱氧化增大表面活性位点，缩短了电子/离子传递途径，进一步提供了高放电容量；在充放电过程中，衍生物作为V₂O₅界面保护层，抑制钒溶解，防止电极结构坍塌。复合材料在电流密度500 mA g^-1下提供了430.6 mAh g^-1的高比容量，同时电池具有优异的倍率性能（在电流密度50A g^-1下比容量为127.1 mAh g^-1）。

    (3) 基于上一章的研究，针对V₂O₅单体材料仍存在电导率低、离子扩散速率慢、放电/充电过程中结构不稳定等缺点，以V₂CT_x MXene为衬底原位生长PANI，氧化还原活性聚合物PANI基于苯胺单体作为结构单元设计实现PANI/V₂CT_x MXene复合正极。V₂CT_x提供了足够的空间来容纳大量的PANI，活性位点增多，可以缩短电子/离子传输途径。由于V₂CT_x MXene显著的导电性，复合材料导电性增高，动力学变快，实现了水系锌离子电池优越的倍率性能。复合正极在电流密度0.5 A g^-1时提供246.9 mAh g^-1，在电流密度15 A g^-1时为172.7 mAh g^-1，并且具有超过10000圈的超长循环，容量保持率高达99.09%。

     Considering the growing demand for smart wearable and portable electronic products, the development of rechargeable energy storage devices with high safety, low cost, low pollution and outstanding energy storage performance has become a problem that has attracted much attention in practical applications. So far, lithium-ion batteries are the earliest rechargeable energy storage devices studied, and are widely used in human life because of their high energy density. However, due to the limited resources of lithium, as well as the lithium has a high cost, so batteries using aqueous electrolytes with metal ions are considered promising alternatives to LIBs. Among these aqueous batteries, aqueous zinc-ion batteries have good application prospects in future practical applications due to their environmental friendliness, higher safety and lower cost. The research objectives of this paper are to improve the specific capacity and cycle stability of MXene-based cathode composites, and to study the diffusion kinetics and zinc storage mechanism, and the conclusions are as follows:

      (1) The Ti₃C₂T_x MXene layer was designed on the surface of the V₂O₅ nanoplate by van der Waals self-assembly method to inhibit the dissolution of vanadium in the electrochemical process, thereby greatly improving the storage performance of zinc ions. The MXene layer on the cathode surface maintains structural integrity and inhibits V dissolution; the heterogeneous interface between V₂O₅ and MXene improved host electrochemical kinetics; Due to the lubricating water molecules in the composite, the electrostatic repulsion between the host layers is reduced, promoting the diffusion of interface Zn²⁺. As a result, the composite shows long-term cycle stability over 5000 cycles，the initial discharge capacity is 345.1 mAh g^-1 at a current density of 500 mA g^-1.

      (2) Based on the research in the previous chapter, the V₂O₅/V₂CT_x MXene composite was weakly oxidized as the positive electrode for Ti₃C₂T_x MXene to be an inert component and could not provide capacity, while V₂O₅/V₂CT_x MXene composites were weakly oxidized as positive electrodes. Under the weak oxidation strategy, V₂CT_x is converted into derivatives V₂O_x@V₂CT_x, and the original MXene conductivity is preserved by the retention of V-C-V bonds. Weak oxidation increases the surfaced active site, shortens the electron/ion transport pathway, and further provides high discharge capacity. During the charging and discharging process, derivatives act as a V₂O₅ interface protective layer to inhibit vanadium dissolution and prevent the collapse of the electrode structure. The composite material provides a high specific capacity of 430.6 mAh g^-1 at 500 mA g^-1, while the battery has excellent rate performance (127.1 mAh g^-1 at 50A g^-1).

      (3) Based on the research in the previous chapter, in view of the shortcomings of V₂O₅ monomer materials, such as low conductivity, slow ion diffusion rate, and structural instability during discharge/charging, PANI was grown in situ with V₂CT_x MXene as the substrate, and the redox active polymer PANI was designed to realize the PANI/V₂CT_x MXene electrode based on aniline monomer as a structural unit. MXene provides enough space to accommodate a large number of PANI, with more active sites, which can shorten the electron/ion transport pathway. Due to the significant conductivity of MXene, the conductivity of the composite is increased and the kinetics become faster, which further improves the specific capacity of the composite. Composited positive electrode provides 246.9 mAh g^-1 at 0.5 A g^-1 and 172.7 mAh g^-1 at 15 A g^-1, and has an ultra-long cycle of more than 10,000 cycles with a capacity retention rate of up to 99.09%.