物理化学学报 >> 2024, Vol. 40 >> Issue (3): 2304036.doi: 10.3866/PKU.WHXB202304036

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气相SiO2复合水凝胶聚合物电解质用于近中性锌-空气电池

裘科, 王凤梅, 廖莫愁, 朱科润, 陈嘉威, 张威, 夏永姚, 董晓丽, 王飞   

  1. 复旦大学化学系, 复旦大学材料科学系, 上海市分子催化与创新材料重点实验室, 上海 200433
  • 收稿日期:2023-04-20 修回日期:2023-05-16 发布日期:2023-05-25
  • 通讯作者: 王飞,Email:feiw@fudan.edu.cn;董晓丽,Email:xldong@fudan.edu.cn;夏永姚,Email:yyxia@fudan.edu.cn E-mail:feiw@fudan.edu.cn;xldong@fudan.edu.cn;yyxia@fudan.edu.cn
  • 基金资助:
    国家重点研发计划(2021YFA1201900)和上海科学技术委员会(21511103300)资助项目

A Fumed SiO2-based Composite Hydrogel Polymer Electrolyte for Near-Neutral Zinc-Air Batteries

Ke Qiu, Fengmei Wang, Mochou Liao, Kerun Zhu, Jiawei Chen, Wei Zhang, Yongyao Xia, Xiaoli Dong, Fei Wang   

  1. Department of Chemistry, Department of Materials Science, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433, China
  • Received:2023-04-20 Revised:2023-05-16 Published:2023-05-25
  • Supported by:
    The project was supported by the National Key R&D Program of China (2021YFA1201900) and the Science and Technology Commission of Shanghai Municipality (21511103300).

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摘要： 近中性锌-空气电池具有对锌负极良好的沉积/剥离相容性和对空气中二氧化碳的化学稳定性，在长循环方面展现出极高的应用前景。然而，液态电解质固有的水分挥发问题和可穿戴设备所需的柔性等需求，限制了这一体系的实际应用。本研究复合了具有高离子电导率和机械强度的聚丙烯酰胺聚合物骨架、具有丰富硅羟基的保水添加剂气相SiO2和对二氧化碳稳定的近中性电解液，制备了气相SiO2复合水凝胶聚合物电解质(SiO2-HPE)。所合成的SiO2-HPE聚合程度高，表面孔道丰富且元素分布均匀。SiO2表面丰富的硅羟基通过改变HPE中的氢键网络，加强了对水分子的束缚，SiO2-HPE因此展现出了良好的保水性、优异的机械性能和较高的离子电导率，是一种理想的柔性锌-空气电池电解质。基于SiO2-HPE组装的近中性锌-空气电池，在相对湿度为30%的条件下，循环寿命可达200 h。此外，基于SiO2-HPE的柔性近中性锌-空气电池器件在弯曲和剪切等特殊条件下都展现出优异的性能，并且可作为电源为不同的用电器供电，是一种极具潜力的下一代电化学储能器件。

关键词: 锌-空气电池, 水凝胶聚合物电解质, 近中性, 气相SiO2, 保水性

Abstract: Near-neutral zinc-air batteries show great promise for long-cycle applications in ambient air owing to their impressive deposition/stripping compatibility with zinc anodes and greater chemical stability towards CO2 in ambient air compared to batteries with traditional alkaline electrolytes. However, the inherent water volatilization of liquid electrolytes and the flexibility of electrolytes required for wearable devices severely limit the practical application of this system. In this study, a fumed SiO2-based composite hydrogel polymer electrolyte (SiO2-HPE) was prepared for application in near-neutral zinc-air batteries. The design of the SiO2-HPE was carried out considering the following three aspects. Firstly, it is widely acknowledged that the polyacrylamide polymer skeleton is beneficial to excellent ionic conductivity and the mechanical strength of the SiO2-HPE. Secondly, fumed SiO2 bearing multiple silicon hydroxyl groups is a suitable option as a water-retaining additive. Thirdly, the near-neutral liquid electrolyte (1 mol·kg-1 Zn(OTf)2) absorbed in the SiO2-HPE is stable towards CO2 in ambient air. In conclusion, these three aspects of the electrolyte design contribute to the practical application of the SiO2-HPE. Raman spectroscopy and scanning electron microscopy revealed that the synthesized SiO2-HPE exhibited a high degree of polymerization, plentiful surface pores, and a uniform distribution of elements. According to the infrared and Raman spectra, the abundant hydroxyl groups located on the surface of the SiO2 particles enhanced water molecule binding by altering the hydrogen bond network within the SiO2-HPE. This conclusion was further confirmed by thermogravimetry and differential scanning calorimetry. After exposure to ambient air (30% relative humidity) for 96 h, the SiO2-HPE exhibited a water retention capacity of 49.52%, which is 6.23% and 1.73% higher than those for 1 mol·kg-1 Zn(OTf)2 and the HPE (hydrogel polymer electrolyte without SiO2). Moreover, owing to the dynamic recombination of the hydrogen bonds between the silicon hydroxyl groups and the gel skeleton, SiO2-HPE exhibited a higher mechanical strength and modulus than HPE under tensile and compressive conditions, respectively. This further rendered it an ideal electrolyte for flexible zinc-air batteries. The near-neutral zinc-air battery assembled with the SiO2-HPE exhibited a cycle life of up to 200 h under 30% relative humidity, far exceeding those of 1 mol·kg-1 Zn(OTf)2 and the HPE. Based on such remarkable performance, the flexible near-neutral zinc-air battery device assembled by the SiO2-HPE has shown a satisfactory performance under special conditions, such as bending and cutting, and can be used as a power supply for different electronic devices, making it a promising next-generation electrochemical energy storage device. Overall, this work provides new insight into the development of flexible zinc-air battery devices with long-term stability in ambient air.

Key words: Zinc-air battery, Hydrogel polymer electrolyte, Near-neutral, Fumed SiO2, Water retention