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The conduction mechanism of a family of high concentration lithium electrolytes (HCEs) is investigated. It is found in all HCEs that the molecular motions are regulated by the anion size and correlated to the HCE ionic resistivity. From the results, a mechanism involving highly correlated ionic networks is derived. [ABSTRACT FROM AUTHOR]

The high price of lithium salts hinders the sustainable development of high concentration electrolytes, while the poor electrochemical performance limits the large-scale application of low concentration electrolytes. Herein, the electrochemical performance of a low concentration electrolyte is improved via dual interfacial modification of the fluoroethylene carbonate (FEC) solvent and the lithium difluoro(oxalato)borate (LiODFB) additive. LiODFB is preferentially oxidized via a ring-opening path to generate a lithium fluoride (LiF)-rich inner layer on the surface of a ferrous lithium phosphate cathode, and then a large amount of C–F polycarbonate oligomers is generated in the outer layer via a reaction between LiODFB and FEC. LiF has a large bandgap and a low lithium ion (Li+) diffusion barrier, and the electronegative C–F groups provide the lithiophilic sites to reduce the interaction between Li+ and solvents, resulting in a repulsive force towards the C＝O dipole of the carbonate ester solvent to improve the oxidation stability of the electrolyte. The clever design of the multi-layer cathode electrolyte interphase suppresses the excessive decomposition of the electrolyte, improves the diffusion of Li+, and enables much-improved cycling stability of the cathodes. This work gives a fruitful insight into the key role of cathode electrolyte interphase components in Li+ diffusion and improves the performance of low-concentration electrolytes. [ABSTRACT FROM AUTHOR]

Transport phenomena and the solvation structure of lithium ions (Li+) and hexafluorophosphate anions (PF6−) in electrolytes with different fluoroethylene carbonate (FEC) concentrations as well as the electrochemical performance and safety of Ni-rich Li-ion battery cells at the 18650 cylindrical cell level are investigated. We have found that the electrolyte with an optimized FEC concentration (25% v/v) can effectively enhance the transport property in terms of the Li+ transference number and contact ion pair (CIP) ratio leading to high performance and safety of practical 18650 cylindrical LIBs. [ABSTRACT FROM AUTHOR]

A rarely porous Li-MOF (Li-AOIA) with surface area of 605 m2 g−1 was employed for the formation of an emerging class of solid-state lithium ion electrolytes. Infiltration of LiBF4 into Li-AOIA afforded Li-AOIA@BF4 with ionic conductivity of 1.09 × 10−5 S cm−1 at room temperature and an activation energy of 0.18 eV. [ABSTRACT FROM AUTHOR]

Fluorinated lithium-rich anti-perovskite (F-LiRAP) is proposed to enhance lithium ion conductivity by creating Frenkel defects that facilitate the formation of lithium-rich and lithium-vacancy couples. We successfully demonstrate an all-solid-state cell configuration based on F-LiRAP, precluding the employment of polymer or liquid additives. [ABSTRACT FROM AUTHOR]

Trace ethanol is applied as a cheap and effective electrolyte additive for reducing the activation voltage of Li2S cathodes in lithium-ion–sulfur batteries. Because Li2S can dissolve in ethanol, the solid–solid phase reaction in the first stage of the activation process converts into a liquid–solid phase reaction, which expedites the transport of electrons and lithium ions and reduces the activation voltage of Li2S. This strategy can be extended to other solvents that can dissolve Li2S. [ABSTRACT FROM AUTHOR]

Electrolytes for lithium-ion batteries (LiBs) have been put aside for too long because a few new solvents have been designed to match electrolyte specifications. Conversely, significant attention has been paid to synthesize new electrode materials and especially positive electrodes. Particularly, most of the studies dedicated to the investigation of electrolytes for LiBs have been focused on mixing different molecules. Currently, the development of high-voltage materials for LiBs stimulates the synthesis of new solvents and new salts that are more stable against oxidation. Despite the challenges, only a few teams are active in this field in developing a rational approach combining physicochemistry, electrochemistry and modelling from the molecular to the macromolecular levels. After assembling a critical collection of physicochemical and electrochemical data from the literature, this study highlights the main trends between the chemical structure of the organic dipolar aprotic solvents and their physicochemical and electrochemical properties to provide a guide for chemists to design new electrolytes for LiBs. This guide also includes indicators to take into account the environmental impact of solvent production by including a life cycle assessment of eight different solvents. [ABSTRACT FROM AUTHOR]

A base–acid hybrid electrolytic system with a low onset voltage of 0.78 V for water electrolysis was developed by using a ceramic Li-ion exchange membrane to separate the oxygen-evolving reaction (OER) in a basic electrolyte solution containing the Li-ion and hydrogen-evolving reaction (HER) in an acidic electrolyte solution. [ABSTRACT FROM AUTHOR]

Direct chemical imaging is critical to understand and control processes that affect the performance and safety of Li-ion batteries. In this work, femtosecond-Laser Induced Breakdown Spectroscopy (fs-LIBS) is introduced for 3D chemical analysis of Li-ion solid state electrolytes in electrochemical energy storage systems. Spatially resolved chemical maps of major and minor elements in solid-state electrolyte Li7La3Zr2O12 (LLZO) samples are presented, with a depth resolution of 700 nm. We implement newly-developed visualization techniques to chemically image the atomic ratio distributions in a LLZO solid state electrolyte matrix. Statistical analysis, 2D layer-by-layer analysis, 2D cross-sectional imaging and 3D reconstruction of atomic ratios are demonstrated for electrolyte samples prepared under different processing conditions. These results explain the differences in the physical properties of the samples not revealed by conventional characterization techniques, and demonstrate the ability of fs-LIBS for direct 3D elemental imaging of Li-ion battery solid-state electrolytes. [ABSTRACT FROM AUTHOR]

Hollow Mn2O3 microspheres have been synthesized by a simple and easy-to-adopt solvothermal method, facilitated by ethanol to obtain the phase pure product at 600 °C. Herein, the ascorbic acid aided inside-out Ostwald ripening promotes the formation of porous microspheres with a hollow interior surface, which is desirable to allow faster transport of lithium ions and to accommodate the volume changes associated with the Mn2O3 anode, especially upon extended cycling. Further, an appreciable high surface area of 426.6 m2 g−1 has been calculated from BET analysis, which is in favour of imparting excellent electrochemical properties that include high reversible capacity, good cycling stability and acceptable rate capability. Interestingly, Mn2O3 hollow microspheres exhibit 425 mA h g−1 under the influence of 1 A g−1 current density, thus qualifying itself as a high rate anode material, bestowed with the added advantage of appreciable high capacity, extractable under nominal current densities. For instance, without requiring the formation of composite, the as-received Mn2O3 anode delivers a steady-state capacity of 760 mA h g−1 at 50 mA g−1 and 610 mA h g−1 at 100 mA g−1, especially after completing 100 cycles. The synergistic advantage of the microspheres containing hierarchically arranged nanostructures and the hollow interior nature with better uptake of the electrolyte results in obtaining promising electrochemical performance from the currently synthesized Mn2O3 anode. [ABSTRACT FROM AUTHOR]

We report the first direct measurement of the extent of the spontaneous non-electrochemically driven reaction between a lithium ion battery electrode surface (Si) and a liquid electrolyte (1.2 M LiPF6–3 : 7 wt% ethylene carbonate : dimethyl carbonate). This layer is estimated to be 35 Å thick with a SLD of ∼ 4 × 10−6Å−2 and likely originates from the consumption of the silicon surface. [ABSTRACT FROM AUTHOR]

Epitaxial thin films of the lithium ionic conductor Li0.17La0.61TiO3 have been successfully synthesized on Al2O3(0001) and Nb:SrTiO3(001) substrates at working temperatures below 750°C using pulsed laser deposition. The application of high laser fluence in conjunction with low oxygen pressure was identified as the key to obtaining highly crystalline Li0.17La0.61TiO3 films. The use of low temperatures prevents the loss of lithium during the deposition process and generates films with no compositional deviation from the target, as confirmed by chemical analyses. The Li0.17La0.61TiO3 film deposited on Al2O3(0001) exhibits a high total ionic conductivity of 3.76 × 10-4 S cm-1 at room temperature, which is comparable to the bulk ionic conductivity of polycrystalline Li0.18La0.16TiO3. The low temperature synthetic process described herein should allow the use of new configurations to fabricate electrode-electrolyte interfaces for use in high power all solid-state batteries incorporating Li0.17La0.16TiO3 as the solid electrolyte. [ABSTRACT FROM AUTHOR]

Epitaxial thin films of Al-doped Li7La3Zr2O12 (LLZO) with a cubic garnet-type structure were successfully synthesized using pulsed laser deposition to investigate the lithium ion conduction in grains. Two orientations of the films were obtained depending on the Gd3Ga5O12 (GGG) substrate orientation, LLZO(001)/GGG(001) and LLZO(111)/GGG(111). The ionic conductivities in the grains of the (001) and (111) films were 2.5 × 10−6 and 1.0 × 10−5 S cm−1 at 298 K, respectively, which were lower than those of polycrystalline LLZO of over 10−4 S cm−1. X-ray reflectometry and inductively coupled plasma mass spectrometry revealed a large amount of Al3+ of over 0.6 moles substituted for Li+. These results indicate that the Al3+ substitution in the LLZO lattice decreases the number of movable lithium ions and blocks the three-dimensional lithium migration pathway. The lattice mismatch between the film and the substrate induced the lattice distortion of the LLZO, resulting in different conductivities between the (001) and (111) films. The epitaxial-film model system directly clarified a substantial impact of the Al substitution and the lattice distortion on the lithium ion conductivity in the LLZO. [ABSTRACT FROM AUTHOR]

We demonstrate that the solvation effect can be the driving force for ion transfer across the water/1,2-dichloroethane interface. Voltammetric behaviours of facilitated Li+ ion transfer by the solvents of lithium-based batteries are investigated, which is valuable for the dual-electrolyte Li–air batteries, but also for the ion detection, separation and extraction. [ABSTRACT FROM AUTHOR]

The copper-catalyzed O2reduction in aqueous electrolyte and the Li-anode in organic electrolyte were united together by a ceramic Li-ions exchange film to form a lithium–air fuel cell. The achieved results demonstrate the cycle between Cu and Cu2O can be used to catalyze O2electrochemical reduction based on the copper-corrosion mechanism. [ABSTRACT FROM AUTHOR]

The copper-catalyzed O2reduction in aqueous electrolyte and the Li-anode in organic electrolyte were united together by a ceramic Li-ions exchange film to form a lithium–air fuel cell. The achieved results demonstrate the cycle between Cu and Cu2O can be used to catalyze O2electrochemical reduction based on the copper-corrosion mechanism. [ABSTRACT FROM AUTHOR]