Chloride solid-state electrolytes for all-solid-state lithium batteries

Journal of Solid State Electrochemistry - Chloride solid-state electrolytes (SSEs) with wide electrochemical windows, high room-temperature ionic conductivity, and good stability towards air have...     

Printed solid-state electrolytes for form factor-free Li-metal batteries

With the ever-growing interest in ubiquitous smart electronics and the Internet of Things, the demand for high-energy-density power sources with aesthetic versatility has increased tremendously. High energy density Li-metal batteries have attracted considerable attention for fulfilling the high energy density requirement of smart electronics. To obtain form factor-free Li-metal batteries with both design diversity and electrochemical reliability, printed solid-state electrolytes are required as a key component because of their viability for the printing/solidification-based fabrication process and electrode-customized chemical/physical properties. This review presents an overview of printed solid-state electrolytes for form factor-free Li-metal batteries with a focus on materials chemistry and fabrication requirements. In addition, their structural/physical/electrochemical properties were discussed in terms of compatibility with Li-metal batteries.     

Cellulose acetate-promoted polymer-in-salt electrolytes for solid-state lithium batteries

Journal of Solid State Electrochemistry - Despite their non-flammability, low processing cost and wide electrochemical stability window, solid-state polymer electrolytes still exhibit certain...     

The challenges and perspectives of developing solid-state electrolytes for rechargeable multivalent battery

Journal of Solid State Electrochemistry - From the perspective of future development trend, energy issues will always accompany with the human development process. The development of new batteries...     

Designing composite solid-state electrolytes for high performance lithium ion or lithium metal batteries

Solid-state electrolytes (SSEs) are capable of inhibiting the growth of lithium dendrites, demonstrating great potential in next-generation lithium-ion batteries (LIBs). However, poor room temperature ionic conductivity and the unstable interface between SSEs and the electrode block their large-scale applications in LIBs. Composite solid-state electrolytes (CSSEs) formed by mixing different ionic conductors lead to better performance than single SSEs, especially in terms of ionic conductivity and interfacial stability. Herein, we have systematically reviewed recent developments and investigations of CSSEs including inorganic composite and organic–inorganic composite materials, in order to provide a better understanding of designing CSSEs. The comparison of different types of CSSEs relative to their parental materials is deeply discussed in the context of ionic conductivity and interfacial design. Then, the proposed ion transfer pathways and models of lithium dendrite growth in composites are outlined to inspire future development of CSSEs.

Composite solid-state electrolytes (CSSEs) formed by mixing different ionic conductors lead to better performance than a single solid-state electrolytes (SSEs), demonstrating great potentials in the next-generation lithium-ion batteries (LIBs).     

All solid-state battery based on ceramic oxide electrolytes with perovskite and NASICON structure

The Li_0.33Lia_0.56TiO₃ and Li_1.3Ti_1.7Al_0.3(PO₄)₃ ceramics with the structures of defect-perovskite and NASICON structures with conductivity of 1–6?×?10^?6 S/cm at the room temperature are obtained. Ceramic electrolytes were developed for a solid-state battery EMF of 4.1 V and high discharge stability in time. Discharge characteristics of solid-state batteries are studied in a laboratory cell.     

Quasi solid-state dye-sensitized solar cell with P(MMA-co-MAA)-based polymer electrolytes

Journal of Solid State Electrochemistry - A series of poly (methylacrylate-co-methylacrylic acid) (P(MMA-co-MAA)) gel polymer electrolytes containing iodide/triiodide (I−/I3−) redox...     

Parametric investigation of laser-induced fluorescence of solid-state uranyl compounds

The combination of remote/standoff sensing and laser-induced fluorescence (LIF) spectroscopy shows potential for detection of uranyl (UO2(2+)) compounds. Uranyl compounds exhibit characteristic emission in the 450-600 nm (22,200 to 16,700 cm(-1)) spectral region when excited by wavelengths in the ultraviolet or in the short-wavelength portion of the visible spectrum. We report a parametric study of the effects of excitation wavelength [including 532 nm (18,797 cm(-1)), 355 nm (28,169 cm(-1)), and 266 nm (37,594 cm(-1))] and excitation laser power on solid-state uranium compounds. The uranium compounds investigated include uranyl nitrate, uranyl sulfate, uranyl oxalate, uranium dioxide, triuranium octaoxide, uranyl acetate, uranyl formate, zinc uranyl acetate, and uranyl phosphate. We observed the characteristic uranyl fluorescence spectrum from the uranium compounds except for uranium oxide compounds (which do not contain the uranyl moiety) and for uranyl formate, which has a low fluorescence quantum yield. Relative uranyl fluorescence intensity is greatest for 355 nm excitation, and the order of decreasing fluorescence intensity with excitation wavelength (relative intensity/laser output) is 355 nm > 266 nm > 532 nm. For 532 nm excitation, the emission spectrum is produced by two-photon excitation. Uranyl fluorescence intensity increases linearly with increasing laser power, but the rate of fluorescence intensity increase is different for different emission bands.     

Solvent effects on the solubilities of reference electrolytes

Solubilities of bis(biphenyl)chromium(I) tetraphenylborate were measured in 25, solubilities of tetraphenylarsonium tetraphenylborate in nine and solubilities of bis(biphenyl)chromium(0) in seven nonaqueous solvents. Linear dependences of the pK_s-values for these compounds as well as the pK_s values for tetraphenylstibonium tetraphenylborate, tetraphenylmethane and tetraphenylgermane were observed. The relations between the pK_s-values of the above mentioned compounds and solvent parameters as well as solvent structure are discussed.     

A concept for synthesis planning in solid-state chemistry

There is a widely-held belief that the preparation of new solid-state compounds based on rational design is not possible. Herein, we present a concept that points the way towards a rational design of syntheses in solid-state chemistry. The foundation of our approach is the representation of the whole material world, that is, the known and not-yet-known compounds, on an energy landscape, which gives information about the free energies of these compounds. From this it follows that all chemical compounds capable of existence are present on this landscape. Thus the chemical synthesis always corresponds to the discovery of compounds, not their creation. Consequently, the first step in planning a synthesis can and must be to identify a synthesizable compound. Up to now, materials capable of existence are discovered in the course of an experimental exploration of the energy landscape; however, an a priori identification of a synthesis goal requires an exploration using theoretical methods. In contrast to those computational approaches currently employed for structure determination for fixed composition and already known unit cells, our aims clash with such restrictions and full global optimizations have to be performed on the landscape. Although for reasons of computational feasibility the accuracy of the energy calculations is not yet as high as one would wish, our approach proves to be surprisingly robust. One always finds the already known compounds of a given chemical system, and, in addition, further plausible structure candidates are discovered. The second step of a rational planning of syntheses is the design of feasible synthesis routes. Modeling such routes requires highly accurate computations for realistic thermodynamic conditions, however this is usually beyond our current capabilities. Thus, we have not seriously pursued such a deductive approach; instead we have attempted, to reproduce the "computational annealing" employed during our structure predictions in the experiment. Educts, generated by vapor deposition methods, that are disperse on an atomic level are found to react with surprisingly low activation energies to give highly crystallized products. However, even this technique does not yet provide the possibility to selectively synthesize a specific solid compound. For this final step, modeling and experimental control of nucleation processes will be the key ingredient. Only when viewed superficially, our goal of a "rational design" of solid-state syntheses and the "high-throughput" syntheses are in contradiction. But an exhaustive exploration of the unimaginably large combinatorial diversity of chemistry remains beyond our capabilities, even with an exceedingly high throughput. The future of solid-state synthesis will be found in a union of these two conceptual approaches.     

Recent advances in solid-state polymer electrolytes and innovative ionic liquids based polymer electrolyte systems

Solid polymer electrolytes are a promising alternative to widely used liquid carbonate electrolytes to deliver next-generation lithium-ion batteries with improved safety. However, the limited ionic conductivity and high interfacial resistance with electrodes limit their widespread use. This review aims to give an overview of the recent research on performance aspects and strategies of solid polymer electrolytes, including ionic conductivity, lithium transference number, design flexibility, scale-up, and integration of ionic liquids with a focus on safety.     

Synthesis and solid-state structures of dimethyl 2,2'-bithiophenedicarboxylates

The syntheses of dimethyl 2,2'-bithiophene-4,4'-dicarboxylate (3), dimethyl 2,2'-bithiophene-3,4'-dicarboxylate (4), and dimethyl 2,2'-bithiophene-3,3'-dicarboxylate (5) are described. Single-crystal X-ray structural analysis of these compounds shows that the thiophene rings in 3 and 4 are nearly coplanar (dihedral angle close to 0 degrees ) and they adopt the anti sulfur conformation in the solid state. Further, the structure of 4 is in agreement with our previous suggestion that there is an electrostatic stabilization of the planar structure due to attraction of the 3-carbonyl oxygen to the sulfur of the distal ring. In 5, however, the thiophene rings are nearly perpendicular (dihedral angle 75 degrees ), indicating considerable steric hindrance between the two large ester groups at the 3- and 3'-positions. Unlike compounds 3 and 4, where the thiophene rings have the sulfur atoms anti, the sulfur atoms in 5 are completely syn. This is the first instance where a bithiophene has been shown to adopt a conformation where the sulfur atoms are completely syn. The solid-state conformations of 3, 4, and 5 are in agreement with ab initio theoretical calculations on these compounds; particularly, the planar conformations of 3 and 4 reflect the previously calculated low rotation barriers of these molecules.     

X-ray photoelectron spectroscopic studies of solid electrolytes

A study of solid electrolytes by X-ray photoelectron spectroscopy reveals that silver (I) and copper (I) compounds generally show very small shifts in electron binding energies. The complex crystal structure of the β-aluminas, however, gives rise to different cation sites which can be distinguished by this technique. Calculations of self-potential show the importance of this term for determining shifts. The possibility of determining the partial ionic charge from the measured shift is also considered.     

Magic-angle-spinning-induced local ordering in polymer electrolytes and its effects on solid-state diffusion and relaxation NMR measurements

Magic-angle-spinning (MAS) enhances sensitivity and resolution in solid-state nuclear magnetic resonance (NMR) measurements. MAS is obtained by aerodynamic levitation and drive of a rotor, which results in large centrifugal forces that may affect the physical state of soft materials, such as polymers, and subsequent solid-state NMR measurements. Here, we investigate the effects of MAS on the solid-state NMR measurements of a polymer electrolyte for lithium-ion battery applications, poly(ethylene oxide) (PEO) doped with the lithium salt LiTFSI. We show that MAS induces local chain ordering, which manifests itself as characteristic lineshapes with doublet-like splittings in subsequent solid-state ¹ H, ⁷ Li, and ¹⁹ F static NMR spectra characterizing the PEO chains and solvated ions. MAS results in distributions of stresses and hence local chain orientations within the rotor, yielding distributions in the local magnetic susceptibility tensor that give rise to the observed NMR anisotropy and lineshapes. The effects of MAS were investigated on solid-state ⁷ Li and ¹⁹ F pulsed-field-gradient (PFG) diffusion and ⁷Li longitudinal relaxation NMR measurements. Activation energies for ion diffusion were affected modestly by MAS. ⁷Li longitudinal relaxation rates, which are sensitive to lithium-ion dynamics in the nanosecond regime, were essentially unchanged by MAS. We recommend that NMR researchers studying soft polymeric materials use only the spin rates necessary to achieve the desired enhancements in sensitivity and resolution, as well as acquire static NMR spectra after MAS experiments to reveal any signs of stress-induced local ordering.     

Nitrosobenzene dimerizations as a model system for studying solid-state reaction mechanisms

Thermal dimerization of nitroso compounds in the solid state was investigated by using para-substituted nitrosobenzenes as model compounds. A mechanism that includes the interplay of topochemical reaction trajectories and phase transfer was proposed on the basis of FT-IR spectroscopic kinetics, time-resolved powder diffraction, and low-temperature X-ray structure determination. From shapes of the kinetic curves analyzed on the basis of the Avrami model, it was found that phase transfer could be triggered by a dimerization reaction of para-substituted nitrosobenzene to azodioxide, which, in turn, can be caused by different packing factors such as disorder in the starting nitroso monomer crystals. Since the represented model can be extended to a broad series of compounds, we propose it as a general method for investigations of solid-state reaction mechanisms.     

Powder crystallography by proton solid-state NMR spectroscopy

The investigation of 1H-1H spin-diffusion build-up curves using a rate matrix analysis approach shows that high-resolution magic angle spinning NMR of protons, applied to powdered organic compounds, provides a method to probe crystalline arrangements. The comparison between experimental 1H data and simulation is shown to depend strongly on the parameters of the crystal structure, for example on the unit cell parameters or the orientation of the molecule in the unit cell, and those parameters are experimentally determined for a model organic compound.     

Selecting indium-containing systems as solid electrolytes

Quasi-binary salt systems InCl₃-MeCl₂, where Me²⁺ stands for Mg²⁺, Cd²⁺, Zn²⁺, Sn²⁺, Co²⁺, or Mn²⁺, in the region of solid solutions on the basis of InCl₃ are considered. A comparative characteristic of some transport properties of these systems is given and optimum compositions for all systems under consideration are determined. The conduction mechanism that presumably takes place in systems InCl₃-MgCl₂ and InCl₃-CdCl₂ is confirmed by data that are obtained with the aid of the Tubandt method. In order to raise the reversibility with respect to the indium ion, also considered is the In₂S₃-InCl₃ system, in which the basis compound is In₂S₃. Methods of electroconduction and XRD are used to establish the existence of a region of limited solid solutions on the basis of indium sulfide. The current efficiency in a system with solid electrolyte In₂S₃-InCl₃ is determined (CE > 50%) and the dependence of the current efficiency on the electrolysis regime is considered. Thermodynamic investigation of some indium-containing compounds and the doping with indium are conducted with use made of indium-containing solid electrolytes of optimum compositions. Data concerning the magnitude of the alteration occurring in the Gibbs energy during the formation of indium-containing semiconducting compounds, which are close to reference data, are obtained.     

Multi-functional zwitterionic compounds as additives for lithium battery electrolytes

A series of multi-functional zwitterionic compounds having both ester and sulfonate groups were synthesized and their electrochemical properties were investigated. The effect of added zwitterionic compounds on the cycling performance of the cell containing 1 M LiPF₆ in EC, DMC, and EMC (1/1/1 by vol.) was also examined. The cell capacity was not varied much at 1/5 C up to 50 cycles with the addition of either 2.25 wt% N-methylpyrrolidinium-N-(propyl sulfonate) (MePyS) or N-methylpiperidinium-N-(propyl sulfonate) (MePipS) as an additive, but dropped significantly at higher C rate of 1 C. Such a sharp decrease of the performance at higher C rate was not observed when MePyS or MePipS was replaced by N-(2-acetoxyethyl) pyrrolidinium-N-(propyl sulfonate) (EsPyS) or N-(2-acetoxyethyl) piperidinium-N-(propyl sulfonate) (EsPipS), implying the positive role of the ester functional group.FT-IR study clearly demonstrates that ester-containing zwitterionic compounds are able to interact with Li⁺ ions through both sulfonate and ester functional groups.     

Li2S-P2S5体系电解质及其在全固态锂离子电池中的应用研究进展

全固态锂离子电池具有安全性能好、能量密度高、工作温区广等优点,被广泛应用于便携式电子设备。固态电解质是全固态锂离子电池的关键材料之一,其中的硫化物电解质具有离子电导率高、电化学窗口宽、晶界电阻低和易成膜等特点,被认为最有希望应用于全固态锂离子电池。本文综述了Li_2S-P_2S_5体系电解质的发展状况,包括固态电解质的制备、改性、表征以及电极/固态电解质之间的固-固界面的稳定兼容问题。本文还涉及了以Li_2S-P_2S_5为电解质的全固态锂离子电池性能的研究进展。     

Molecular imprinting using monomers with solid-state polymerization

Molecular imprinting of two diolefinic compounds with solid-state photopolymerization, 2,5-distyrylpyrazine (DSP) and diethyl p-phenylenediacrylate (EPA), was demonstrated. Solid nanoscale particles of the monomer were produced and deposited onto the surface of a surface acoustic wave (SAW) transducer using the technique known as rapid expansion of supercritical solutions (RESS). The particles were polymerized by UV light in the presence of an alkane template vapor. Both imprinted and non-imprinted devices were tested upon exposure to a variety of alkane vapors in the gas phase. The results demonstrate an enhanced sensitivity to vapors at or below the size of the template. A size exclusion mechanism of recognition is proposed.