Solid-state Lithium Rechargeable Batteries Research Articles

PVDF-HFP/LLZTO composite electrolytes with UV cure for solid-state lithium rechargeable batteries

PVDF-HFP/LLZTO composite electrolytes with UV cure for solid-state lithium rechargeable batteries

Preparation of new composite electrolytes for solid-state lithium rechargeable batteries by compounding LiTFSI, PVDF-HFP and LLZTO

Preparation of new composite electrolytes for solid-state lithium rechargeable batteries by compounding LiTFSI, PVDF-HFP and LLZTO

Pre-treatments of Lithium Foil Surface for Improving the Cycling Life of Li Metal Batteries

Liquid electrolytes used in Li-ion batteries are flammable and slowly degrade to form a solid electrolyte interface (SEI) that irreversibly consumes lithium, decreasing the Coulombic efficiency of the battery. In addition, lithium anodes undergo severe morphology changes during cycling and Li dendrites are formed, which may cause short-circuits inside the battery. Safety concerns and the requirement of higher energy density have stimulated a search for a durable solid-state lithium rechargeable battery (SSLB) with an inorganic or dry polymer electrolyte that is more stable toward the lithium metal and suppresses the growth of lithium dendrites. Reducing the reactivity and increasing the poor contact between solid interfaces in these all-solid-state batteries remain challenging and Li-surface modification is one option to be explored to remedy these problems. Here, we review recent progress in surface pre-treatment of 2D lithium foil to enhance the electrochemical performance of various battery configurations. The review is organized based on the different types of modification reported in the literature.

Polyethylene oxide/garnet-type Li6.4La3Zr1.4Nb0.6O12 composite electrolytes with improved electrochemical performance for solid state lithium rechargeable batteries

Next generation lithium batteries require new electrolytes with good safety, excellent ionic conductivity, high electrochemical stability and good cycling performance. Herein, we first report a solid composite polymer electrolyte comprises of Li6.4La3Zr1.4Nb0.6O12 fillers and polyethylene oxide matrix. The ionic conductivity of the solid composite electrolyte is significantly improved to 1.4 × 10−3 S cm−1 (60 °C) and the electrochemical window is enhanced to 5.2 V, respectively, by incorporation of Li6.4La3Zr1.4Nb0.6O12 powder at a weight ratio of 0.5:1 with respect to polyethylene oxide. The solid batteries employing the composite electrolytes are able to work at room temperature and have a capacity retention of 99% after cycle. The performance improvement is primarily due to the combined functions of each component in the composite: (i) the incorporation of fillers effectively decreases the crystallinity of PEO, providing more amorphous region for ion conduction; (ii) Li6.4La3Zr1.4Nb0.6O12 serves as a fast ion conductor in the composite and enhance the electrochemical stability; (iii) the polymer matrix forms intimate surface contact with fillers and electrodes, reducing the bulk and interfacial resistance. The composite polymer electrolyte in this work would be a competitive alternative for the next generation solid state lithium rechargeable batteries.

Electrochemical Nature of the Cathode Interface for a Solid-State Lithium-Ion Battery: Interface between LiCoO2 and Garnet-Li7La3Zr2O12

Garnet-structured solid electrolytes have been extensively studied for a solid-state lithium rechargeable battery. Previous works have been mostly focused on the materials’ development and basic electrochemical properties but not the cathode/electrolyte interface. Understanding the cathode interface is critical to enhance chemical stability and electrochemical performance of a solid-state battery cell. In this work, we studied thoroughly the cathode/electrolyte interface between LiCoO2 and Li7La3Zr2O12 (LLZO). It was found that the high-temperature process to fuse LiCoO2 and LLZO induced cross-diffusion of elements and formation of the tetragonal LLZO phase at the interface. These degradations affected electrochemical performance, especially the initial Coulombic efficiency and cycle life. In a clean cathode interface without the thermal process, an irreversible electrochemical decomposition at > ∼ 3.0 V vs Li+/Li was identified. The decomposition was able to be avoided by a surface modification of LLZO (...

Characterization of thin-film electrolytes for all solid-state batteries

In this study, amorphous lithium thio-germanate thin-films were prepared as electrolytes for solid-state lithium rechargeable batteries by using RF sputtering deposition in an Ar atmospheres. High quality lithium germanium sulfide, nLi2S + GeS2(n = 1, 2, and 3) thin-films have been successfully made by RF sputtering and synthesized as solid-state electrolytes. Although these materials are unstable in air the thin-films were thoroughly characterized by X-ray diffraction (XRD), Scanning electron spectroscopy (SEM), Raman spectroscopy, Infrared spectroscopy (IR), and impedance spectroscopy using special setups to prevent contamination. The ionic conductivities of the thin-films are ∼3 order magnitude higher than reported values for oxide thin-films. In this way, this work may provide a new way for developing new thin-film electrolytes for solid-state lithium ion batteries.

Anomalous lithium ion migration in the solid electrolyte (Li2S)7(P2S5)3; fast ion transfer at short time intervals studied by PGSE NMR spectroscopy

The sulfide-based solid electrolyte (Li2S)7(P2S5)3 has large ionic conductivity, and thus is an important candidate for application to solid-state lithium rechargeable batteries. In lithium solid conductors, a small lithium ion (Pauling ionic radius of 60 pm) migrates in space composed of standing anions, and such situations are not yet well understood experimentally as well as theoretically. Lithium ion migration for the crystalline (Li2S)7(P2S5)3 was observed over short observation times using the pulsed-gradient spin-echo (PGSE) 7Li nuclear magnetic resonance (NMR) techniques. Diffusive diffraction effects were apparent in the echo attenuation profiles indicating that motion of lithium ions was in some way constrained to a certain (i.e., ‘characteristic’) length scale. Prior to being diffracted, the lithium ions rapidly migrate similar to lithium ions in liquids. The diffractive behavior depends on observation time and the strength of the applied pulsed magnetic field gradient (PFG), which suggests that the diffusing lithium ions are distributed. The diffraction patterns give a longer characteristic distance for faster moving lithium ions. Diffusing lithium ions collide with obstacles such as standing anions many times at longer time intervals, which consequently results in slow migration. We believe that our findings will contribute to understand conduction mechanisms in solid conductors.

Lithium ion diffusion in solid electrolyte (Li2S)7(P2S5)3 measured by pulsed-gradient spin-echo 7Li NMR spectroscopy

The sulfide based solid electrolyte (Li2S)7(P2S5)3 has large ionic conductivity, and thus its application in solid-state lithium rechargeable batteries as an electrolyte has been developed. We observed the 7Li and 31P nuclear magnetic resonance (NMR) spectra of crystallized (Li2S)7(P2S5)3 in the steady state and found that narrow and broad components coexist in wide temperature range of the 7Li resonance. The measurement of 7Li ion diffusion was performed for the narrow component between 303 and 353K by the pulsed-gradient spin-echo (PGSE) NMR method. Lithium ion diffusion scattered in a polydispersive manner and the apparent diffusion constants of the Li+ (DLi) varied depending on measurement conditions at a certain temperature. The temperature-dependent ionic conductivity was observed from 263 to 353K and the activation energy was 31.4kJmol−1 for the crystallized (Li2S)7(P2S5)3. The DLi evaluated from ionic conductivity using the Nernst-Einstein relation was consistent with the scattering apparent DLi observed by the PGSE NMR method. The translational movement of Li+ observed by the PGSE NMR is extremely complex. Within a short distance and a short period, Li+ ions move quickly and slow down with time and distance. This is the first trial to measure the lithium diffusion directly for continuous space in the solid electrolyte.

Electrolytes for solid-state lithium rechargeable batteries: recent advances and perspectives

This critical review presents an overview of the various classes of Li(+) conductors for use as electrolytes in lithium polymer batteries and all-solid state microbatteries. Initially, we recall the main models for ion transport and the structure-transport relationships at the basis of the observed conductivity behaviours. Emphasis is then placed on the physico-chemical and functional parameters relevant for optimal electrolytes preparation, as well as on the techniques of choice for their evaluation. Finally, the state of the art of polymer and ceramic electrolytes is reported, and the most interesting strategies for the future developments are described (121 references).

Nanomaterials for Lithium-ion Rechargeable Batteries

In lithium-ion batteries, nanocrystalline intermetallic alloys, nanosized composite materials, carbon nanotubes, and nanosized transition-metal oxides are all promising new anode materials, while nanosized LiCoO2, LiFePO4, LiMn2O4, and LiMn2O4 show higher capacity and better cycle life as cathode materials than their usual larger-particle equivalents. The addition of nanosized metal-oxide powders to polymer electrolyte improves the performance of the polymer electrolyte for all solid-state lithium rechargeable batteries. To meet the challenge of global warming, a new generation of lithium rechargeable batteries with excellent safety, reliability, and cycling life is needed, i.e., not only for applications in consumer electronics, but especially for clean energy storage and for use in hybrid electric vehicles and aerospace. Nanomaterials and nanotechnologies can lead to a new generation of lithium secondary batteries. The aim of this paper is to review the recent developments on nanomaterials and nanotechniques used for anode, cathode, and electrolyte materials, the impact of nanomaterials on the performance of lithium batteries, and the modes of action of the nanomaterials in lithium rechargeable batteries.

A facile route to thin-film solid state lithium microelectronic batteries

We describe the synthesis and characterization of a thin-film solid state lithium rechargeable battery. This battery was designed for integration into a multi-chip module (MCM). The battery consists of a spin-on Ag 2WO 4 — polymer cathode, a lithium hexaflurophosphate — polymer-impregnated microporous nylon membrane electrolytic separator, and a lithium foil anode. Kapton™ was used as the substrate and encapsulating top layer of the battery. The battery had a total area of approximately 4.0 cm 2 , thickness of 0.6 mm, and weighed 0.4 g. The battery had an open circuit voltage of 3.5 V and was able to deliver a current density of 0.05 mA/cm 2 for 1.5 h while maintaining a voltage above 2.0 V. The battery was cycled over 12,000 times between 3.5 and 2.0 V using a constant discharging current density of 0.1 mA/cm 2 and charging current density of 0.05 mA/cm 2. The battery was designed for integration into a standard 96 pin Kovar/Glass Bead quad-flatpack programmable MCM (1.42×1.42×0.16 in.). The charging and discharging characteristics of this battery are presented and discussed in terms of its intended application.

Thermal behavior of new polymer electrolytes

AbstractSolid polymer electrolytes (SPE) have been identified as a class of materials which could enable the fabrication of high energy density solid state lithium rechargeable batteries which could meet the performance requirements for advanced portable electronic and automotive applications. In order to achieve this goal, novel SPE systems having high ionic conductivity and good mechanical properties at or near ambient temperature must be developed. Novel lithium salts believed to be useful in realizing this objective have recently been proposed. The thermal behavior of SPE systems based on high molecular weight poly(ethylene oxide) (PEO) and on two novel salts, the lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and the lithium tris(trifluoromethylsulfonyl)‐methanide (LiTSFM) is reported and compared with the thermal behavior of the high molecular weight PEO–lithium trifluoromethane sulfonate (LiTFLT) SPE system. Phase diagrams for the PEO–LiTFSI and PEO–LiTFSM SPE systems have been established and are discussed in terms of their impact on SPE‐based rechargeable lithium battery technologies. The use of a novel plasticizer in conjunction with the PEO–LiTFSI‐based SPE system is reported and it is shown how this modifies the thermal behavior of the PEO–LiTFSI SPE system.

Polyaniline used as a positive in solid-state lithium battery

The composite film of polyaniline containing a complex of poly(ethylene oxide) (PEO) and lithium perchlorate was prepared and used as a positive in solid-state lithium rechargeable battery. The charge and discharge behaviour at constant current density of 0.1 and 0.2 mA/cm 2, recycleability and the rate of self-discharge were measured at room temperature. The preliminary results showed that the composite positive of polyaniline exhibited a good compatibility with polymer solid-state electrolyte and its service life was up to 250 cycles at deep charge/discharge between 2.5 and 4.0 V. The coulombic efficiency and the capacity density of the Li/PAN solid-state rechargeable battery were 98% and 48.3 A h/kg, respectively (based only on positive active material).