柔性可穿戴技术的发展要求柔性储能器件具有可充电循环性，高能量密度等特性。可充电柔性锌-空气电池能够满足这些要求，有望成为下一代柔性储能器件。但依旧面临着众多的挑战，例如充放电循环性能差，使用寿命短，容量低等问题。因此，如何提升电池的充放电循环性能，延长使用寿命，提高容量等，成为可充电柔性锌-空气电池的关键。可充电柔性锌-空气电池是一个整体，需要进行系统地研究。 为了从整体上提升电池性能，我们对电池中的催化剂、空气电极、凝胶电解质以及锌电极等关键组件进行了设计与优化。结合溶剂热法与快速热处理，制备了超薄Co₃O₄纳米片，增大了比表面积，调节了表面结构，从而加快催化过程电荷转移，提升催化性能。结合电沉积法与热处理，制备了超薄Co₃O₄／碳布一体化电极，优化催化剂与基体之间界面，减小界面电阻，增强界面结合力，提升催化性能与弯曲性能。在PVA-KOH碱性凝胶电解体系中引入了四乙基氢氧化铵(TEAOH)，加强凝胶内部分子间的相互作用，提升保水能力，减少因脱水而产生的形变，维持电解质与电极之间的接触界面，延长电池使用寿命。利用泡沫铜模板，制备三维锌电极，增大与凝胶电解质间的接触界面，提升大电流密度下的充放电性能，增大面积比容量。主要工作包括： 1.采用溶剂热法和快速热处理相结合，制备了超薄Co₃O₄纳米片。H₂O₂能将乙二醇部分氧化生成β-羟基乙酸，使其选择性吸附在前驱体表面，让前驱体平面生长，同时起到氧化剥离作用，对超薄前驱体的形成起到至关重要的作用。 超薄Co₃O₄纳米片能够提升比表面积，增加与反应物之间的接触面积，同时表面具有特殊的原子排布和电子结构和有利催化反应的不饱和配位的Co，其ORR和OER性能相比商业Co₃O₄纳米颗粒分别提高了25％和50％。以超薄Co₃O₄纳米片作为双功能催化剂，所组装的纤维型可充电柔性锌-空气电池的体积容量和能量密度分别达到7.7AhL⁻¹和7.3 WhL⁻¹，在1.6mA㎝⁻³电流密度下，可稳定循环8h。纤维型可充电柔性锌-空气电池的放电电压几乎不受弯曲影响，在1.6 mA㎝⁻³下放电可保持在1.10 V左右，并且能够编织入衣物驱动电子器件。 2.乙二醇(EG)的吸附作用能够抑制Co(OH)₂在垂直方向上的生长，使其在碳布(CC)表面沿平面生长形成超薄结构，加以热处理转化成超薄介孔Co₃O₄／CC一体化空气电极。 原位生长的超薄介孔Co₃O₄／CC一体化电极不仅能够增大催化剂与基体之间的接触界面，减小界面电阻，加快电荷转移，而且超薄结构有利于提升催化性能，其ORR和OER活性可达到14.34 mAg⁻¹和298.3 mAg⁻¹，分别约为商业Co₃O₄／CC的28倍和12倍。以超薄介孔Co₃O₄／CC作为空气电极，所组装的锌-空气电池在2mA㎝⁻²的电流密度下循环，放电平均电压≈1.03V，充电平均电压≈1.95V，充放电电压差≈0.92V，能量利用效率=52.8％，并可稳定循环工作10h以上。在2， 5，10mA㎝⁻²的放电电流密度下，面积比容量分别为5.42，5.00，4.95 Ah㎝⁻²，能量密度分别为5.42，4.62，4.02 Wh ㎝⁻²。超薄介孔Co₃O₄／CC的催化剂与基体之间具有更强的结合力，拥有良好的机械稳定性能和弯曲稳定性能，经过300次反复弯曲后，放电平台和放电时长分别仅下降了0.01V和0.04 h，并且在不同弯曲状态下，充放电循环性能几乎不受影响。 3.将TEAOH引入PVA-KOH-H₂O体系中，制备了PVA-TEAOH-KOH-H₂O碱性凝胶电解质。TEAOH的引入增强了凝胶电解质中的氢键作用，提升了保水性能，并且能够抗电解质碳酸化。同时，PVA-TEAOH-KOH-H₂O碱性凝胶电解质保持了PVA-KOH-H₂O碱性凝胶电解质的初始离子电导率，减缓了离子电导率的下降。 PVA-TEAOH-KOH-H₂O碱性凝胶电解质具有良好的保水性能，因失水而产生的形变小，能保持与电极之间的接触面积，同时拥有良好的离子电导率。所组装的锌-空气电池在电流密度为2mA㎝⁻²时，循环寿命在66.6h以上，高于PVAKOH-H₂O碱性凝胶电解质的37 h。 4.通过电镀的方法在泡沫铜上沉积了金属锌，从而成功制备了三维锌电极。碱性电镀环境下，溶液的扩散性更好，锌更容易在泡沫铜骨架上沉积。所制备的三维锌电极具有更大的比表面积，增大了与碱性凝胶电解质之间的接触界面，从而提高放电电压，降低充电电压，增大面积比容量。在5 mA㎝⁻²的放电电流密度下，初始放电电压可以达到1.11 V，同时放电的面积比容量可以达到10.55 mAh ㎝⁻²。并且拥有更好的充放电循环性能，在5 mA ㎝⁻²的电流密度下，可循环30 h(90个循环)以上，平均放电电压从1.08 V下降至0.87 V，平均充电电压从2.08 V上升至2.19 V。 关键词：锌-空气电池；四氧化三钴；一体化电极；凝胶电解质；三维锌电极

 The development of flexible and wearable technology requires flexible energy storage devices with rechargeability and high energy density. The rechargeable and flexible zinc-air battery can meet these requirements, making it promissing to be the next generation of flexible energy storage devices. However, it still faces many challenges, such as poor charge and discharge performance, short life and low capacity. Therefore, how to improve the charge and discharge performance, prolong the life and increase the capacity, etc. has become the key to the rechargeable and flexible zinc-air battery. The rechargeable and flexible zinc-air battery is a whole system and needs to be systematically studied. In order to improve the battery performance, we designed and optimized the key components such as catalyst, air electrode, gel electrolyte and zinc electrode. Ultrathin Co₃O₄ nanosheets were prepared by combining solvothermal method and fast heat treatment. The specific surface area was increased and the surface structure was adjusted, which accelerated the charge transfer and improved the performance. Combined with electrodeposition and heat treatment, an ultrathin Co₃O₄/CC integrated electrode was prepared to optimize the interface between the catalyst and the substrate, thus reduce the interface resistance, enhance the interfacial adhesion, and improve the catalytic performance and bending performance. The introduction of tetraethylammonium hydroxide (TEAOH) in the PVA-KOH alkaline gel electrolyte system enhanced the interaction between the molecules inside the gel, improved the water retention capacity, reduced the deformation caused by dehydration, maintained the contact interface with the electrode, and prolonged the battery life. The 3D Zn electrode was prepared by using the copper foam as template to increase the contact interface with the gel electrolyte, improve the charge and discharge performance at a large current density, and increase the area specific capacity. The main work includes: 1.Ultrathin Co₃O₄ nanosheets were prepared by solvothermal method and fast heat treatment. H₂O₂ could partially oxidize ethylene glycol to form β-glycolic acid, which could selectively adsorb on the surface of the precursor, facilitating the horizontal growth of the precursor, and at the same time acted as an oxidative exfoliation. H₂O₂ played a critical role in the formation of ultrathin precursors. Ultrathin Co₃O₄ nanosheets could increase the specific surface area and increase the contact area with the reactants. At the same time, the surface had a special atomic arrangement and electronic structure, and an unsaturated coordination Co which was favorable for catalytic reaction. The ORR and OER performance were improved by 25% and 50% compared to commercial Co₃O₄ nanoparticles, respectively. Using ultrathin Co₃O₄ nanosheets as a bifunctional catalyst, at a current density of 1.6 mA ㎝⁻³, the volumetric capacity and energy density of the assembled fiber-type rechargeable and flexible Zn-air battery reached 7.7 Ah L⁻¹ and 7.3 Wh L⁻¹, and the battery could stably cycle for 8 h. The discharge voltage of the fiber-type rechargeable and flexible Zn-air battery was almost unaffected by the bending, which maintained at about 1.10 V at 1.6 mA ㎝⁻³. Moreover, the battery could be woven into the clothes and drived electronic devices. 2.The adsorption of ethylene glycol (EG) could inhibit the vertical growth of Co(OH)₂, so that Co(OH)₂ horizontally growed on the carbon cloth (CC) to form an ultrathin structure, and transformed into ultrathin mesoporous Co₃O₄/CC integrated air electrode by heat treatment. In-situ growth of ultrathin mesoporous Co₃O₄/CC could increase the contact interface between the catalyst and the substrate, reduce the interface resistance, accelerate charge transfer, and the ultrathin structure was beneficial to improve the catalytic performance. The ORR and OER performance could reach 14.34 mA g⁻¹ and 298.3 mAg⁻¹, approximately 28 and 12 times of commercial Co₃O₄/CC. Using ultrathin mesoporous Co₃O₄/CC as air electrode, when the assembled Zn-air battery cycled at a current density of 2 mA ㎝⁻², the average discharge voltage was ≈1.03 V, the average charge voltage was ≈1.95 V, and the charge-discharge voltage gap was ≈0.92 V, energy utilization efficiency was≈52.8%. The battery could stably cycle for more than 10 h. At the discharge current density of 2,5,10 mA ㎝⁻², the area specific capacities were 5.42, 5.00, 4.95 Ah ㎝⁻², and the energy densities were 5.42, 4.62, and 4.02 Wh ㎝⁻², respectively. The ultrathin mesoporous Co₃O₄/CC had stronger bonding force between the catalyst and the substrate, so that it had good mechanical stability and bending stability. After 300 bending cycles, the discharge platform and discharge duration only decreased by 0.01 V and 0.04 h, respectively. Furthermore, the charge and discharge cycle performance was almost unchanged under various bending conditions. 3.PVA-TEAOH-KOH-H₂O alkaline gel electrolyte was prepared by introducing TEAOH into PVA-KOH-H₂O system. The introduction of TEAOH enhanced hydrogen bonding in the gel electrolyte, improved water retention, and increased resistance to electrolyte carbonation. At the same time, the PVA-TEAOH-KOH-H₂O alkaline gel electrolyte maintained the initial ionic conductivity of the PVA-KOFI-H₂O alkaline gel electrolyte, and slowed down the decline of ionic conductivity. The PVA-TEAOH-KOH-H₂O alkaline gel electrolyte had good water retention performance and high ionic conductivity. The deformation caused by water loss was small, which could maintain the contact area with the electrode. The assembled Zn-air battery had a cycle life of more than 66.6 h at a current density of 2 mA ㎝⁻², which was higher than that of the PVA-KOH-H₂O alkaline gel electrolyte for 37 h. 4.3D Zn electrode was successfully prepared by electroplating metallic zinc on the copper foam. In an alkaline plating environment, the solution was more diffusible and zinc was more likely to deposit on the skeleton of copper foam. The prepared 3D Zn electrode had a higher specific surface area and increased the contact interface with the alkaline gel electrolyte, thereby increasing the discharge voltage, lowering the charging voltage, and increasing the area specific capacity. At a discharge current density of 5 mA ㎝⁻², the initial discharge voltage could reach 1.11 V, and the discharge area specific capacity could be 10.55 mAh ㎝⁻². And the battery with good charge and discharge cycle performance, could cycle for 30 h (90 cycles) at a current density of 5 mA ㎝⁻², and the average discharge voltage droped from 1.08 V to 0.87 V, and the average charging voltage rose from 2.08 V to 2.19 V. Key Words: Zn-air battery, Co₃O₄, Integrated electrode, Gel electrolyte, 3D Zn electrode