Inorganic Lithium Ion Conductors Research Articles

Inorganic lithium-ion conductors for fast-charging lithium batteries: a review

Inorganic lithium-ion conductors for fast-charging lithium batteries: a review

Solid State Li-Metal Battery Based on Novel Polymer Electrolyte

Conventional Li-ion batteries (LIBs) with unique advantages, exhibit a limited cycle life and significant safety problems due to the flammable organic solvent electrolytes. A solid-state battery (SSB) utilizing a solid electrolyte can potentially address the above issues. However, despite recent advancements, a truly commercially viable candidate for SSB electrolyte remains elusive. Although inorganic lithium-ion conductors are available, their practical applications have been mainly hindered by interfacial issues, since it is very challenging to construct intimate contact between the solid electrode and solid electrolyte due to their rigidity in conventional SSBs, leading to high polarization and low utilization of active materials. Storagenergy Technologies, Inc. has developed a novel polymer electrolyte that exhibits high Li+ conductivity, wide electrochemical window, and wide operational temperature. We also demonstrated a simple but effective interfacial engineering approach to improve the active material utilization via in-situ polymerization process. Complete characterization including cycling life, rate capability, thermal stability, calendar life and safety testing of coin cells and pouch cells with develop polymer electrolyte will be presented.

Mitigating Interfacial Issues in All-Solid-State Batteries

All Solid-State Batteries (ASSB), by replacing liquid electrolyte with solvent-free solid electrolyte, have the potential to ultimately resolve the safety issues of Li-ion batteries (LIBs). Although inorganic lithium-ion conductors are available, their practical applications have been mainly hindered by interfacial issues, since it is very challenging to construct intimate contact between the solid electrode and solid electrolyte due to their rigidity in conventional ASSBs, leading to high polarization and low utilization of active materials. Herein, we developed a solid polymer electrolyte (SPE) that exhibits high Li+ conductivity of >1.2 mS/cm at room temperature and wide electrochemical window (~4.8 V vs. Li/Li+), and we also demonstrate a simple but effective interfacial engineering approach to mitigate the poor interfacial contact via in-situ polymerization process. The investigation revealed that the polymerization process of SPE plays a significant role in interfacial resistance between electrodes and electrolytes in large format pouch cells. Complete characterization of ASSBs with two SPE systems (in-situ polymerization vs. ex-situ polymerization) will be compared and presented, as well as the cell lifetime under galvanostatic cycling.

Influence of the Lithium Substructure on the Diffusion Pathways and Transport Properties of the Thio-LISICON Li4Ge1–xSnxS4

Inorganic lithium-ion conductors have garnered considerable attention as separators for all-solid-state lithium-ion battery applications, given their potential to solve the safety issues and improve the energy and power densities of conventional devices possessing liquid electrolytes. However, achieving this transition requires the optimization of solid electrolyte materials and thus, developing a better understanding of the structure–property relationships, that govern ionic transport, is of crucial importance. Herein, inspired by the growing technological interest, a systematic study on the correlations between structural modifications and transport properties in the thio-LISICON family resulting from the substitution of Ge4+ by Sn4+ within Li4Ge1–xSnxS4 has been conducted. Using Rietveld refinements against neutron diffraction data coupled with maximum-entropy method analyses of nuclear densities, a rigorous investigation into the Li+ diffusion pathways was performed. The substitution of Ge4+ by Sn4+ i...

Flexible sulfur wires (Flex-SWs)—A new versatile platform for lithium-sulfur batteries

A simple electrospinning methodology is described for generating novel fiber configurations of sulfur with the potential of yielding high performance sulfur electrodes for use in lithium-sulfur batteries. The unique fiber morphology derived by electrospinning has the capability of generating flexible sulfur yarns for the first time rendering them a highly attractive platform for small-scale mobile device applications such as textile-batteries. The electrospinning methodology reported herein also allows for the formation of a polymer-sulfur interface which acts as a physical barrier to liquid lithium electrolyte facilitating the reduction of polysulfide dissolution, a primary barrier to the progress of Li-S systems. Such flexible sulfur wire materials when converted into pellet sulfur electrodes, exhibit very stable capacities over 135 cycles with high areal capacities (∼2.5mAhcm−2). Coating the electrodes with an inorganic lithium ion conductor coating results in further improvement of cycling behavior with electrodes of ∼650mAhg−1 capacity and an impressive low fade rate of ∼0.003% fade cycle−1 demonstrating the promise of this unique platform.

Deposition and Dissolution of Lithium through Lithium Phosphorus Oxynitride Thin Film in Some Ionic Liquids

Electrochemical deposition and dissolution of lithium were investigated in 1-butyl-1-methylpyrrolidinium (BMP+) and 1-ethyl-3-methylimidazolium (EMI+) bis(trifluoromethylsulfonyl)amide (TFSA–) ionic liquids containing LiTFSA through a typical inorganic lithium ion conductor, lithium phosphorus oxynitride (LiPON) thin film. In both BMPTFSA and EMITFSA containing 1 M LiTFSA, no cathodic current attributable to reductive decomposition of the ionic liquids was observed on the Ni electrode coated with the LiPON thin film. Electrochemical deposition and dissolution of Li were confirmed to occur through the LiPON thin film in both ionic liquids. Therefore, the LiPON thin film acted as an artificial solid electrolyte interphase film, in which Li ion was transported from the ionic liquids to the interface between the Ni electrode and the LiPON thin film.

Deposition and Dissolution of Lithium through Lithium Phosphorus Oxynitride Thin Film in Some Ionic Liquids

Aprotic ionic liquids have been studied as alternative electrolytes for rechargeable lithium batteries because of non-volatility, which is expected to improve safety of the batteries. However, most of the organic cations giving room-temperature ionic liquids are instable against metallic lithium. In case of carbonate-based organic electrolytes, a passivation film, so called solid-electrolyte interphase (SEI) film, is known to form as a result of reductive decomposition of organic solvents. The SEI film is considered as a lithium ion conductor, though its nature has not been clarified yet. On the other hand, the reductive decomposition of the organic cations of ionic liquids hardly leads to formation of good SEI film. In the present study, electrochemical deposition and dissolution of lithium were investigated in some aprotic ionic liquids through a typical inorganic lithium ion conductor, lithium phosphorus oxynitraide (LiPON), thin film. Reversible deposition and dissolution of lithium were possible on a nickel electrode covered with LiPON thin film in bis(trifluoromethylsulfonyl)amide (TFSA–) based ionic liquids consisting of 1-butyl-1-methylpyrrolidinium (BMP+) and 1-ethyl-3-methyl imidazolium (EMI+). No cathodic current attributable to reductive decomposition of these cations was observed on the LiPON-coated electrodes, indicating that LiPON thin film acted as an artificial SEI film and that lithium ions were transported between the ionic liquids and LiPON. The deposition of lithium between the nickel electrode and LiPON thin film was confirmed by electrochemical quartz crystal microbalance (EQCM) measurements and X-ray photoelectron spectroscopy.

リチウムイオン伝導性を有するａ‐６０Ｌｉ２Ｓ・４０ＳｉＳ２非晶質体とＳＥＰＳ熱可塑性エラストマーとの複合体の作製

Organic-Inorganic composites were prepared as lithium ion conducting materials. Organic thermo-elastic co-polymer SEPS (styrene-ethylene-propylene-styrene) and inorganic lithium ion conductor a-60Li2S⋅0SiS2 (mol%), which was prepared by mechanical milling processes, were used as raw materials for the preparation of the composite materials. The mixture of the raw materials were heated at 90°C under a pressure of about 3×107 Pa for 1 h to obtain the composite materials in sheet shape. The obtained composite sheet containing 7wt% of SEPS showed ion conductivity 4.9×10-5 Scm-1 at room temperature. Electronic polarization measurements suggested that the main carrier of the composite sheet was lithium ions and that the ion transport number of the sheet was almost unity.

Bibliographical Review on Inorganic Lithium Ion Conductors

A bibliographical review of inorganic lithium ion conductors is presented with a focus on those potential candidates for lithium battery application. A wide variety of inorganic lithium ion conductors, both crystalline ceramics and non-crystalline glasses, are considered.