论文总字数：21458字

摘 要

锂离子电池自1990年代商业化以来，发展了约30年，它对减缓全球变暖，有效利用化石燃料和可再生能源具有重要的作用，但目前锂离子电池在目前各个方面的使用中，能量密度并不足够，新型的工艺和技术迫切需要得到发展。

聚合物电解质具有相比于有机液体电解质更高的安全性能。聚合物电解质可分为凝胶型电解质和全固态型电解质。无机电解液有一个大的电化学窗口，具有良好的电化学性能等优点，但是无机电解液具有不好的机械特性，不能承受很大的负荷。。一旦隔膜被破坏或者断裂，将会引发电池的短路，造成电池安全，容量，商业化生产等一系列问题，严重影响电池的使用。本课题结合两种电解质的优点，拟采用无机物聚合物复合的方式制备出NZSP-PEO复合钠离子固态电解质应用于钠离子电池，解决商用有机电解质易燃，产生枝晶现象严重的安全性问题，解决锂金属成本过高，提高商用价值的问题。由此开展工作如下：

本实验通过采用添加5 wt % Na₂SiO₃的NZSP为原料，将无机材料NZSP和聚合物PEO按照1:1质量比混合，通过简单的固相法制备出NZSP复合钠离子固态电解质膜。制得的NZSP-PEO复合钠离子固态电解质膜具有较高的离子电导率，约为0.68 mS cm^-1，商用玻璃纤维隔膜的离子电导率也在0.8 mS cm^-1左右。通过进行的SEM，XRD，力学性能测试，电化学性能测试等得出这种复合电解质膜具有相当优异的表现，完全可以满足钠离子电池在生产和生活中的正常使用。NZSP复合钠离子固态电解质膜组装的电池也有优异的循环性能和倍率性能。因此研究聚合物和无机物复合的固态电解质在解决电池产生钠枝晶的安全问题，解决锂金属成本过高的问题等方面，从而提高电池的综合性能。

因此得出如下结论：

为了解决钠离子电池钠成本较高，钠离子电池中枝晶现象较锂离子电池更严重的现象，选用成本更低的钠金属和安全性更高的固态电解质。但是纯聚合物电解质的电化学稳定性不高，而且在抑制枝晶产生方面的性能表现不好，但是机械性能比较好；纯无机电解质对钠很稳定，但是机械性能差,无法承受较大的压力,在电池的批量生产方面可行性不大。因此考虑选择无机物NZSP（Na₃Zr₂Si₂PO₁₂)和有机物PEO（聚氧化乙烯）聚合，兼顾无机物电解质和有机物电解质共同的优点，可用于提高电池性能。由实验数据可得，制备出的复合聚合物电解质具有很好的性能，可用于组装钠离子电池。采用磷酸矾钠为正极，NZSP-PEO聚合物电解质膜组装的钠离子电池测试得到的伏安特性曲线，放电容量，循环性能和倍率性能都比较良好。因此，为了解决电池安全性能和电化学性能，以及兼顾成本和商业化使用等目的的NZSP复合钠离子固态电解质薄膜具有优异的性能，具有应用前景。

关键词：钠离子电池 聚合物固态电解质 偏硅酸钠 PEO

Preparation and Properties of NZSP Composite Sodium Electrolyte

Abstract

Lithium ion battery has been developed for about 30 years since its commercialization in the 1990s.Polymer electrolyte has higher safety performance than organic liquid electrolyte.Once the diaphragm is damaged or broken, it will lead to a short circuit of the battery, resulting in a series of problems such as battery safety, capacity, commercial production, and seriously affecting the use of the battery. Combining the advantages of the two electrolytes, this project plans to use inorganic polymer composite method to prepare a new electrolyte to solve the safety problrm and cast the reduction of the batteries. The work is as follows:

In this experiment, the inorganic material NZSP and polymer PEO were mixed according to the mass ratio of 1:1 by adding 5 wt % Na₂SiO₃ to NZSP as raw materials, and the NZSP composite sodium ion solid-state electrolyte membrane was prepared by a simple solid-state method. The prepared NZSP-PEO composite sodium ion solid electrolyte membrane has high ionic conductivity, about 0.68 mS cm^-1, and the ionic conductivity of commercial glass fiber membrane is also about 0.8 mS cm^-1. Through SEM, XRD, mechanical property test and electrochemical property test, it is concluded that the composite electrolyte membrane has excellent performance, which can fully meet the normal use of sodium ion battery in production and life. The cells assembled by NZSP composite sodium ion solid electrolyte membrane also have excellent cycle performance and rate performance. Therefore, the study of polymer and inorganic composite solid-state electrolyte can solve the safety problem of sodium dendrite and the problem of high cost of lithium metal, so as to improve the comprehensive performance of the battery.

Therefore, the following conclusions are drawn:

In order to solve the problem that sodium cost is high and dendrite phenomenon is more serious than lithium-ion battery, sodium metal with lower cost and solid electrolyte with higher safety are selected. However, the electrochemical stability of pure polymer electrolyte is not high, and its performance in inhibiting dendrite generation is not good, but its mechanical performance is relatively good; pure inorganic electrolyte is very stable for sodium, but its mechanical performance is poor, and it can not bear large pressure, so it is not feasible in batch production of batteries. Therefore, the choice of inorganic NZSP (Na₃Zr₂Si₂PO₁₂) and organic PEO (polyoxyethylene) polymerization is considered. Therefore, in order to solve the safety and electrochemical performance of the battery, as well as considering the cost and commercial use, nzsp composite sodium ion solid electrolyte film has excellent performance and application prospect.

Key words: Sodium ion battery; Polymer solid electrolyte; Sodium metasilicate; PEO

目 录

摘要 I

Abstract III

第一章 绪论 1

1.1引言 1

1.2 钠离子电池简介 1

1.2.1钠离子电池发展概况 2

1.2.2 钠离子电池工作原理 3

1.2.3 钠离子电池正极材料 3

1.2.4 钠离子电池负极材料 5

1.2.5 钠离子电池电解质 5

1.3 聚合物电解质简介 6

1.3.1 聚合物电解质发展概况 6

1.3.2 聚合物电解质分类 6

1.4 研究目的和研究内容 7

1.4.1 研究目的 7

1.4.2 研究内容 8

第二章 实验材料与研究方法 11

2.1实验试剂 11

2.2实验仪器 11

2.3材料物理性能表征 14

2.3.1形貌表征 14

2.3.2力学性能表征 14

2.4.1离子电导率测试 14

2.4.2线性扫描伏安测试 14

2.4.3循环伏安测试 14

2.4.4恒流充放电测试 14

第三章 NZSP复合钠离子固态电解质 17

3.1引言 17

3.2 NZSP复合钠离子固态电解质的制备 17

3.3 NZSP复合钠离子固态电解质的物理性质 18

3.3.1表面微观形貌 18

3.3.2力学性能 19

3.4 NZSP复合钠离子电解质的电化学性质 20

3.4.1离子电导率 20

3.4.2电化学窗口 21

3.4.3循环伏安曲线 21

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