Development of sodium hybrid quasi-solid electrolytes based on porous NASICON and ionic liquids

Lithium-ion batteries are currently the alternative of choice to overcome the increasing demand of energy. However, besides the scarcity of lithium and limited geolocation, it is believed that such batteries have already reached their maximum maturity. Sodium batteries emerge as an alternative to produce the new, so called, post-lithium batteries. In this study, we explore (i) the effect of sodium content and sintering temperature in solid electrolytes based in NASICON-type compounds and (ii) the use of two methodologies to obtain porous NASICON samples: application of natural substances and organic materials as pore-formers and freeze casting. The main purpose is the attainment of hybrid quasi-solid state electrolytes, with enhanced room temperature conductivity, based on porous ceramic electrolyte layers infiltrated with ionic liquids. Using this approach, porous samples with different microstructure and porous morphology and distribution were achieved, providing an enhancement in conductivity (ranging from 0.45 to 0.96 mS cm⁻¹ at 30 °C) of one order of magnitude for infiltrated samples respect to pore-free samples. According to these results the porous NASICON might be considered as a functional macroporous inorganic separator that can act as a Na⁺ reservoir.     

Solid-state potentiometric SO2 sensor combining NASICON with V2O5-doped TiO2 electrode

A compact tubular sensor based on NASICON (sodium super ionic conductor) and V₂O₅-doped TiO₂ sensing electrode was designed for the detection of SO₂. In order to reduce the size of the sensor, a thick-film of NASICON was formed on the outer surface of a small Al₂O₃ tube; furthermore, a thin layer of V₂O₅-doped TiO₂ with nanometer size was attached on the NASICON as a sensing electrode. This paper investigated the influence of V₂O₅ doping and sintering temperature on the characteristics of the sensor. The sensor attached with 5 wt% V₂O₅-doped TiO₂ sintered at 600 °C exhibited excellent sensing properties to 1–50 ppm SO₂ in air at 200–400 °C. The EMF value of the sensor was almost proportional to the logarithm of SO₂ concentration and the sensitivity (slope) was −78 mV/decade at 300 °C. It was also seen that the sensor showed a good selectivity to SO₂ against NO, NO₂, CH₄, CO, NH₃ and CO₂. Moreover, the sensor had speedy response kinetics to SO₂ too, the 90% response time to 50 ppm SO₂ was 10 s, and the recovery time was 35 s. On the basis of XPS analysis for the SO₂-adsorbed sensing electrode, a sensing mechanism involving the mixed potential at the sensing electrode was proposed.     

Na3Zr2Si2PO12固态电解质研究进展

钠离子电池具有资源丰富、能量密度高等优点,使用固态电解质的固态钠电池兼具高安全性成为研究热点。固态电解质是超离子导体,是固态电池关键材料。Na₃Zr₂Si₂PO₁₂是钠超离子导体（NASICON）中最具代表性的固态电解质材料。总结了Na₃Zr₂Si₂PO₁₂材料的结构、离子传输机制及其相互关系,旨在从机理上理解Na₃Zr₂Si₂PO₁₂固态电解质中钠离子传输性能;总结了主要制备方法,指出了不同方法的优缺点;在提升离子电导率方面,对合成工艺、掺杂、界面因素进行了总结,力求归纳和探索合成高性能钠离子固态电解质的途径。     

粉末尺寸对等离子喷涂 Na3Zr2Si2PO12 电解质成分和组织结构的影响

全固态钠离子电池由于安全性和元素丰度等天然优势, 在大规模储能领域具有巨大的应用潜力。 全固态电 池的核心是固态电解质, NASICON 型的 Na3Zr2Si2PO12(NZSP) 电解质因为离子电导率高、 热稳定性与力学性能优 异等优点而受到广泛关注。 本研究采用大气等离子喷涂沉积单个 NZSP 扁平粒子和沉积体, 系统研究了粉末粒度 分布和喷涂参数对 NZSP 粒子元素蒸发和沉积体组织结构的影响。 通过沉积单个粒子, 揭示了等离子喷涂参数对 NZSP 粉末粒子的熔化程度和 Na、 P 元素优先蒸发的影响规律。 结果表明, 等离子电弧功率与氢气流量对其蒸发 影响显著, 元素蒸发损失量存在明显的粒子尺寸效应, 粒径小于约 35 μm 时, 随粒径的减小, Na 与 P 的蒸发损 失量显著增加, 当粒径增加至 35 μm 以上时, Na 与 P 的蒸发损失量受粒径的影响显著减小且整体损失量也有限; 通过对粒径范围的控制能够将等离子喷涂过程中 Na 元素的损失量控制在 10 % 以下, P 元素损失量控制在 20 % 以下。 采用粒径范围 30~50 μm 的 NZSP 粉末, 结合大气等离子喷涂参数控制可以得到无明显层状结构的良好层 间结合的组织结构致密电解质, 表明大气等离子喷涂在全固态钠离子电池固态电解质的制备中具有广阔的应用前 景。     

低功耗微型CO2传感器的研制

制作了一种新型微型结构CO2传感器,该传感器采用Al2O3陶瓷片作为衬底,sol-gel法制备的固体电解质NASICON(sodiumsuperionicconductor)材料为离子导电层,复合碳酸盐Li2CO3-BaCO3(摩尔比为1:1.5)为敏感电极。该传感器在CO2浓度为(500~5000)×10–6体积分数范围内表现出良好的敏感特性,灵敏度达到67.3mV/decade(毫伏/10×10–6体积分数),并且功耗由原来的1.08W降到0.72W。微型元件的响应恢复时间分别为20s和58s。     

Synthesis of Na ion-electron mixed conductor Na3Zr2Si2PO12 by doping with transition metal elements (Co,Fe, Ni)

NASICON solid electrolyte Na₃Zr₂Si₂PO₁₂ (NZSP) exhibits high chemical stability and can be utilized as cladding materials of cathodes to improve battery cycle stability. However, the electronic conductivity of NZSP is extremely low (∼10⁻⁹ S cm⁻¹), which will hinder the electron conduction of cathode materials. To address this issue, the electronic conductivity of NZSP is improved by doping with transition metal elements (Co, Fe, Ni). Co-doped NZSP has an electronic conductivity of 5.03 × 10⁻⁶ S cm⁻¹. On the other hand, the ionic conductivity of doped samples remains stable, even slightly increased. The mechanical properties of pristine and doped samples are characterized with a micro indenter, which is also a key parameter for coating materials.     

NASICON基NO_2气体传感器

文中介绍了一种管式结构的固体电解质NO_2气体传感器.该传感器是用溶胶–凝胶法制备的NASICON(钠离子导体) 为导电层材料,利用化学沉淀法制备的NiO和贵金属Au作为敏感电极材料制得的.文中研究了不同敏感电极材料对气体传感器性能的影响.以NiO+Au 作为敏感电极材料的传感器具有较大的灵敏度,当工作温度在300 ℃时,对浓度为(5～200)×10-6的NO_2表现出了良好的气敏性能,传感器的灵敏度大于70 mV/decade.     

NASICON固体电解质气体传感器的研究进展

采用高温固相法、溶胶-凝胶法制备了NASICON固体电解质材料,并利用XRD、IR、Raman、SEM等现代分析手段对NASICON材料进行了分析表征,优选出NASICON材料制备的工艺条件.对制备不同检测气体所需的敏感电极材料组份及制备方法进行了比较系统的研究.并以NASICON为离子导电层,以BaCO3-Li_2CO_3、Na_2SO_4-Li_2SO_4等复合盐以及单一或复合金属氧化物为敏感电极材料,制作出了具有良好性能的CO_2、CO、SO_2、NO_2、H_2S、Cl_2、NH_3等分立器件和集成一体化的CO-C_7H_8(甲苯)、NH_3-C_7H_8两种双功能器件.     

Determination of the p-electronic conduction parameter of NASICON by potentiometric measurements

Using the galvanic cell: