基于强粘接凝胶电解质的锌离子电池的制备及其低温电化学性能

Preparation and low-temperature electrochemical performance of Zn-ion battery based on a robust adhesion hydrogel electrolyte

  • 摘要: 凝胶基固态锌离子电池作为柔性储能器件具有良好的机械稳定性、环境友好性和高安全性,在可穿戴设备领域日益受到关注,但存在因界面接触差和易冻结限制了凝胶基固态电池在低温环境中的使用性能。因此,如何设计和开发具有良好界面稳定性和低温适应性的凝胶基固态锌离子电池是亟待解决的问题。本文以丙烯酰胺(AAm)、银/木质素纳米粒子(Ag@Lignin NPs)、纳米羟基磷灰石(HAp)和氯化锌(ZnCl2)为原料制备具有强自粘性的抗冻凝胶电解质,将其与金属Zn电极、聚苯胺(PANI)层层组装制备成具有强界面作用的Zn|凝胶电解质|PANI锌离子电池,研究了界面粘接强度的影响规律及其低温电化学性能。研究结果表明:电解质中Ag@Lignin NPs丰富的邻苯二酚官能团赋予凝胶强粘接性能,使其与Zn电极的界面韧性和剪切强度在–60℃时分别达467.4 J·m−2和95.7 kPa。随后,对凝胶电解质与Zn电极的界面相容性进行研究,Ag@Lignin NPs的引入降低了Zn||Zn对称电池的过电位,且在–60℃的环境温度下仍保持稳定的沉积/剥离行为。制备的Zn||PANI固态电池表现出优异的耐低温性能,在–60℃下电容量最高可达22.1 mA·h·g−1。与此同时,Zn||PANI固态电池具有优异的循环稳定性,在–40℃下循环充/放电300次,平均库仑效率为95.83%,电容量保持率为65.20%。更重要的是,制备的锌离子电池具有良好的变形稳定性,在经历20%应变40次拉伸循环后其电容量保持率达88.3%,展示出优异的柔性性能。

     

    Abstract: The hydrogel-based solid-state Zn-ion batteries have attracted increasing attention in the wearable electronics as flexible energy storage due to their good mechanical stability, eco-friendliness and safety. However, their performance is limited in low temperature owing to weak interfacial adhesion and easily freezing. Therefore, how to design and develop hydrogel-based solid Zn-ion batteries with excellent interface stability and low temperature adaptability is an urgent problem to be solved. In this paper, an anti-freezing hydrogel electrolyte with high self-adhesion was prepared by introducing nanohydroxyapatite (HAp), Ag@Lignin nanoparticles (Ag@Lignin NPs), and zinc chloride (ZnCl2) into the polyacrylamide (PAAm) network. Zn|hydrogel electrolyte|PANI Zn-ion battery with robust interfacial toughness was prepared in a layer-by-layer assembly with Zn metal electrode, hydrogel electrolyte and polyaniline (PANI). This work has investigated the effect of interfacial adhesion and low-temperature electrochemical performance. The results show that the abundant catechol groups of Ag@Lignin NPs in the hydrogel electrolyte endow the hydrogel with robust adhesion, reaching a high interfacial toughness of 467.4 J·m−2 and shear strength of 95.7 kPa at –60℃ for the hydrogel electrolyte/Zn. Then, the interfacial compatibility between the hydrogel electrolyte and Zn electrode was studied, which indicates that the introduction of Ag@Lignin NPs reduces the overpotential of the Zn|hydrogel electrolyte|Zn symmetric cell, thus enabling stable Zn plating/stripping cycles even at –60℃. The assembled Zn||PANI solid-state battery exhibits excellent low-temperature performance, delivering high capacity of 22.1 mA·h·g−1 at –60℃. Meanwhile, the Zn||PANI solid-state battery demonstrates satisfactory cycling stability, with an average coulombic efficiency of 95.83% and a capacity retention of 65.20% after 300 charging/discharging cycles at –40℃. More encouragingly, the assembled Zn-ion battery presents impressive deformation stability, which is able to tolerate dynamic tension deformations and sustain high capacity retention of 88.3% after 40 tension cycles at 20% strain, showing excellent flexible performance.

     

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