Inorganic Composite Electrolyte Research Articles

Organic-Inorganic Composite Electrolytes Optimized with Fluoroethylene Carbonate Additive for Quasi-Solid-State Lithium-Metal Batteries.

Composite solid electrolytes (CSEs) are considered crucial materials for next-generation solid-state lithium batteries with high energy density and reliable safety, and they make full use of the advantages of both organic and inorganic solid-state electrolytes. However, few CSEs have sufficiently high ionic conductivity at room temperature for practical applications. Here, a traditional CSE consisting of poly(ethylene oxide) (PEO) matrix and Li1.3Al0.3Ti1.7(PO4)3 (LATP) fillers was optimized by introducing a fluoroethylene carbonate (FEC) additive, resulting in an improved high ionic conductivity of 1.99 × 10-4 S cm-1 at 30 °C. The symmetric Li||Li cell assembled with the optimized CSE exhibited a low overpotential and a good cycling stability of more than 1500 h at room temperature. Moreover, the Li||LiFePO4 battery with the optimized CSE delivered a discharge capacity of 132 mAh g-1 at 0.2 C after 300 cycles at room temperature. Comparisons between the LATP-containing CSE and control electrolytes indicated that the enhanced ion conductivity of the former resulted from the synergistic effect of LATP and FEC. Comprehensive characterizations and DFT calculations suggest that with the presence of LATP, FEC additives in the precursor could transform into some other species in the preparation process of CSE. It is believed that these FEC-derived species improve the ion conductivity of the CSEs. The results reported here may open up new approaches to developing composite electrolytes with high ionic conductivity at room temperature by introducing organic additives in the precursor and converting them into species that facilitate ion conduction in the CSE preparation process.

Poly(ionic liquid)-functionalized graphene oxide towards ambient temperature operation of all-solid-state PEO-based polymer electrolyte lithium metal batteries

Endowing polyethylene oxide (PEO)-based electrolyte with low crystallinity and high efficient Li+ transport channels is urgently required for next generation all-solid-state lithium metal batteries (LMBs). Herein, a new type of oxyethyl containing poly(ionic liquid) modified graphene oxide nanoparticles (ox-PIL@GO) is coincidentally proposed for preparing PEO based organic–inorganic composite electrolyte membranes (CPEs). Both experimental and DFT simulation results indicate that the dissociation of the LiTFSI is significantly enhanced by the anticipated electrostatic interaction between imidazolium cation and TFSI- anions in CPEs. In addition, the formed electrostatic interaction can also inhibit the movement of TFSI-, giving rise to the increased lithium transference number of 0.61 from 0.21 for the neat PEO/LiTFSI electrolyte. Furthermore, the ion–dipole interaction between imidazolium cation and PEO chain largely reduces the crystallinity of PEO and the ionic conductivity of 1.01 × 10-4 S cm−1 at 40 °C is successfully obtained. As a result, the ox-PIL@GO incorporated PEO electrolyte enables the Li||Li symmetric cell with long-term, square-wave galvanostatic cycling test of 800 h at current density of 0.1 mA cm−2 at 50 °C and the solid-state LiFePO4|CPE|Li battery with high discharge specific capacity of 116 mAh g−1 at 40 °C at 1C for 300 cycles.

Organic-inorganic multi-scale enhanced interfacial engineering of sulfide solid electrolyte in Li-S battery

The developing sulfide solid electrolyte is a promising way to overcome shuttle effect of polysulfide in the traditional liquid Li-S battery. However, an air stable sulfide solid electrolyte and competitive solid–solid interface structure must be constructed firstly. Herein, we have designed an organic–inorganic multi-scale composite electrolytes to overcome the interfacial issues of solid state Li-S batteries (SSLSBs). The organic–inorganic composite electrolyte consists of a gel polymer electrolyte (GPE) and an oxygen doped inorganic sulfide solid electrolyte. The O doped sulfide solid electrolyte improves its chemical stability and suppresses the lithium dendrites. A thin GPE film protects the crystal structural stability during cycles and greatly enhances the performance of O doped sulfide solid electrolyte due to the GPE not only constructs soft interface contact between S cathode and solid electrolyte, but also builds lithium ion transport paths by ionic liquid between them. Those SSLSBs display a very good cycling performance with the specific capacity of 1023 mAh/g after 50 cycles at 60 °C and 541 mAh/g after 150 cycles at 30 °C under same rate of 0.1 C. This study demonstrates that the development of advanced solid-state Li-S battery needs to fully integrate a number of technical advantages.

Application of a composite electrolyte in a solid-acid fuel cell system: A micro-arc oxidation alumina support filled with CsH2PO4

A micro-arc oxidation alumina (MOA) support filled with a CsH2PO4 proton conductor was investigated as an inorganic composite electrolyte for a H2/O2 solid-acid fuel cell (SAFC). The MOA support was polycrystalline and contained α- and γ-Al2O3 phases; while, the proton conductor CsH2PO4 formed an interlaced network within the MOA support. The single-module SAFC using the fabricated MOA/CsH2PO4 membrane delivered a peak power of ∼38.5 m W cm−2 and a proton conductivity of ∼2.1 m S cm−1 at a low temperature (25 °C). Compared to a SAFC using an anodic alumina membrane composite electrolyte (AAM/CsH2PO4 SAFC), which displayed rapid degradation, the SAFC using the MOA/CsH2PO4 composite electrolyte showed improved stability with cycling. This was attributed to the crystalline α-Al2O3 phase that was part of the MOA support that had increased the chemical resistance.

Enhanced performance of a direct methanol alkaline fuel cell (DMAFC) using a polyvinyl alcohol/fumed silica/KOH electrolyte

A novel polymer–inorganic composite electrolyte for direct methanol alkaline fuel cells (DMAFCs) is prepared by physically blending fumed silica (FS) with polyvinyl alcohol (PVA) to suppress the methanol permeability of the resulting nano-composites. Methanol permeability is suppressed in the PVA/FS composite when comparing with the pristine PVA membrane. The PVA membrane and the PVA/FS composite are immersed in KOH solutions to prepare the hydroxide-conducting electrolytes. The ionic conductivity, cell voltage and power density are studied as a function of temperature, FS content, KOH concentration and methanol concentration. The PVA/FS/KOH electrolyte exhibits higher ionic conductivity and higher peak power density than the PVA/KOH electrolyte. In addition, the concentration of KOH in the PVA/FS/KOH electrolytes plays a major role in achieving higher ionic conductivity and improves fuel cell performance. An open-circuit voltage of 1.0 V and a maximum power density of 39 mW cm −2 are achieved using the PVA/(20%)FS/KOH electrolyte at 60 °C with 2 M methanol and 6 M KOH as the anode fuel feed and with humidified oxygen at the cathode. The resulting maximum power density is higher than the literature data reported for DMAFCs prepared with hydroxide-conducting electrolytes and anion-exchange membranes. The long-term cell performance is sustained during a 100-h continuous operation.

Dye-sensitized solar cell with a solid state organic–inorganic composite electrolyte containing catalytic functional polypyrrole nanoparticles

An organic–inorganic composite electrolyte with tetra-n-butyl titanate and ethylene glycol is prepared with sol–gel method and used in fabricating solid state dye-sensitized solar cell (S-DSSC). The addition of acetyl acetone into the composite electrolyte can extend the solidification time to meet the time requirement for assembling S-DSSC. The addition of 4-tert-butylpyridine can enhance the photovoltaic performance of S-DSSC due to its efficient suppressing of dark current in S-DSSC. Furthermore, with the addition of catalytic functional polypyrrole nanoparticles for transformation of iodide/triiodide redox couples in the composite electrolyte, the energy conversion efficiency of S-DSSC increases from 3.147 to 3.597%, with 14% enhancement.

A novel cesium hydrogen sulfate–zeolite inorganic composite electrolyte membrane for polymer electrolyte membrane fuel cell application

Abstract A new type of CsHSO 4 –HZSM-5 inorganic composite electrolyte membrane is prepared by mechanically mixing CsHSO 4 (CHS) and nanometer-scale HZSM-5 zeolite powders. The effects of HZSM-5 on the crystallite structure, proton conductivity, and thermal stability of the CsHSO 4 electrolyte are investigated. Incorporation of HZSM-5 is found to significantly increase the low-temperature proton conductivity of the CsHSO 4 electrolyte, extending its operating temperature down to 100 °C. The composite electrolyte with 40 mol% HZSM-5 shows the highest proton conductivity in the measured temperature range. The low-temperature activation energy of the composite with 40 mol% HZSM-5 is lower than that of the CHS–SiO 2 composite. The improvement of the proton conductivity can be attributed to the enhanced interfacial interaction between the two phases. And the small HZSM-5 particles lead to a change in the bulk properties of the ionic salts. The melting point of the CHS–HZSM-5 composite electrolyte is lower than that of the pure CHS electrolyte. The CHS–HZSM-5 composite electrolyte is suitable for polymer electrolyte membrane fuel cells operated at 100–200 °C.

Advances in anodic alumina membranes thin film fuel cell: CsH 2PO 4 pore-filler as proton conductor at room temperature

Anodic alumina membranes (AAM) filled with cesium hydrogen phosphate proton conductor have been tested as inorganic composite electrolyte for hydrogen–oxygen thin film (≤50 μm) fuel cell (TFFC) working at low temperatures (25 °C), low humidity ( T gas = 25 °C) and low Pt loading (1 mg cm −2). Single module TFFC delivering a peak power of around 15–27 mW cm −2, with open circuit voltage (OCV) of about 0.9 V and short circuit current density in the range 80–160 mA cm −2 have been fabricated. At variance with pure solid acid electrolytes showing reproducibility problems due to the scarce mechanical resistance, the presence of porous alumina support allowed to replicate similar fuel cell performances over numerous AAM/CsH 2PO 4 assemblies. A scale-up process of the electrodic area has been optimized in order to increase the delivered peak power of AAM thin film fuel cell. Morphological, chemical and electrochemical studies on the alumina composite electrolyte have been carried out by means of scanning electron microscopy, X-ray diffractometry, Micro-Raman spectroscopy, DTA/DTG analysis, ac impedance spectroscopy and single fuel cell tests.

Quasi-solid-state dye-sensitized solar cells based on a sol–gel organic–inorganic composite electrolyte containing an organic iodide salt

An organic–inorganic composite gel electrolyte based on TiO 2 gel, γ-butyrolactone (γ-BL) and N-methyl pyridine iodide was prepared by the sol–gel method. This gel electrolyte shows high ambient ionic conductivity of 7.63 mS cm −1, which is close to the data of liquid electrolyte with the same organic iodide salt and γ-butyrolactone. Based on the gel electrolyte, a quasi-solid-state dye-sensitized solar cell was fabricated and the highest overall energy conversion efficiency of light-to-electricity of 3.06% was achieved under irradiation of 60 mW cm −2.

Structural Study of Inorganic Oxides in a Hybrid Organic−Inorganic Solid Polymer Electrolyte

Polymer−inorganic composite electrolytes very often show superior properties as compared to simple polymer electrolytes, and this enhancement is often ascribed to the structure and interfacial properties of the composite. Here, the structure of aluminosilica (AlSi) domains formed within organic−inorganic solid polymer electrolytes was studied using solid state 29Si and 27Al magic angle spinning (MAS) NMR, transmission electron microscopy (TEM), and nitrogen sorption experiments following material calcinations, to determine how the composite affects the properties in this class of polymer electrolytes. The major feature of all the calcined AlSi's based on 600 MW poly(ethylene glycol) (PEG) is the presence of two types of morphologies: nanoparticles with sizes of about 20−60 nm, and larger platelike particles. Increasing the amount of AlSi in the organic−inorganic composite material (OICM) increases the fraction of platelike particles relative to nanoparticles. The nanoparticles are practically nonporous, ...