All-solid-state Lithium-sulfur Batteries Research Articles

Polymer-based electrolytes for all-solid-state lithium–sulfur batteries: from fundamental research to performance improvement

With the increasing demand for a higher energy density and a lower cost energy storage system, lithium–sulfur batteries have become one of the promising candidates to replace current Li-ion batteries. However, in liquid electrolyte systems, the lithium dendrite growth and the shuttle effect cause severe safety hazard as well as capacity decay, which hinders the commercialization of practical lithium–sulfur batteries. Polymer-based electrolytes provide a promising solution to these challenges. This type of electrolyte, including polymer and composite polymer electrolytes, demonstrates the capabilities to prevent polysulfide dissolution and suppress lithium dendrite growths, while ensuring good surface contact and high flame resistance. This review summarizes the most recent progress of polymer-based all-solid-state lithium–sulfur batteries (ASSLSB), which revealed mechanisms and challenges of electrolyte ionic conductivity, reaction mechanism, anode/electrolyte interface, and cathode/electrolyte interface. Based on these revealed principles, possible solutions to these challenges such as the addition of inorganic fillers, interface modification, utilization of different types of lithium salt and polymers are introduced. In addition, the state-of-the-art approaches with great performance improvement are highlighted in this review. Finally, we provide perspectives on research directions that can further the understanding and development of polymer-based ASSLSB.

Confining Sulfur in Porous Carbon by Vapor Deposition to Achieve High-Performance Cathode for All-Solid-State Lithium–Sulfur Batteries

All-solid-state lithium–sulfur batteries (ASLBs) have the potential to achieve high energy density because of sulfur’s high theoretical capacity (1672 mAh g–1) while alleviating persistent polysulf...

A novel air-stable Li7Sb0.05P2.95S10.5I0.5 superionic conductor glass-ceramics electrolyte for all-solid-state lithium-sulfur batteries

The blend of air stability and high lithium-ion (Li+) conductivity is not a simplistic approach to attain for sulfide-based solid-state electrolytes (SSEs), which hinders the exploitation of high energy all-solid-state lithium-sulfur batteries (ASSLSBs). Herein we report a novel lithium superionic conductor of Li7Sb0.05P2.95S10.5I0.5 as solid-state glass-ceramics electrolytes obtained by an annealing treatment in a solid-state reaction route. It systematically explores the impact of facile aliovalent dual doping into the newly synthesized solid electrolytes, which have influenced higher Li+ conductivity of 2.55 × 10−3 Scm−1 at room temperature, and wide range of voltage stability vs. Li/Li+ up to 7 V. Except that, an activation barrier of Li7Sb0.05P2.95S10.5I0.5 for Li+ migration drops expressively due to optimizing the dopant contents, and subsequently defects produced. The electrolyte also achieved significant air stability based on Hard and Soft Acid/Base (HSAB) theory. The intrinsic structural aspects of the air stability for Li7P3S11 and Li7Sb0.05P2.95S10.5I0.5 solid-state electrolytes are premeditated using a combination of ex-situ X-ray photoelectron spectroscopy, XRD as well as Raman spectroscopy and SEM. The Li2S-VGCF-SSE composite cathode with Li7Sb0.05P2.95S10.5I0.5 SSE exhibited a high initial discharge capacity of 622.3 mAhg−1 at 0.060 mAcm−2, and ASSLSB was retained over 683.3 mAh g−1 after 15th cycle at room temperature, better than pristine Li7P3S11 SSE-based cell. This research provides a novel concept on the design of air-stable and superionic conductor solid-state electrolytes for high-performance ASSLSBs.

Rational Designed Mixed-Conductive Sulfur Cathodes for All-Solid-State Lithium Batteries.

All-solid-state lithium-sulfur batteries (ASSLSBs) hold great promise for safe and high-energy-density energy storage. However, developing high-performance sulfur cathodes has been proven difficult due to low electronic and ionic conductivities and large volume change of sulfur during charge and discharge. Here, we reported an approach to synthesize sulfur cathodes with a mixed electronic and ionic conductivity by infiltrating a solution consisting of Li3PS4 (LPS) solid electrolyte and S active material into a mesoporous carbon (CMK-3). This approach leads to a uniform dispersion of amorphous Li3PS7 (L3PS) catholyte in an electronically conductive carbon matrix, enabling high and balanced electronic/ionic conductivities in the cathode composite. The inherent porous structure of CMK-3 also helps to accommodate the strain/stress generated during the expansion and shrinkage of the active material. In sulfide-based all-solid-state batteries with Li metal as the anode, this cathode composite delivered a high capacity of 1025 mAh g-1 after 50 cycles at 60 °C at 1/8C. This work highlights the important role of high and balanced electronic and ionic conductivities in developing high-performance sulfur cathodes for ASSLSBs.

Totally compatible P4S10+n cathodes with self-generated Li+ pathways for sulfide-based all-solid-state batteries

All-solid-state lithium sulfur batteries (ASSLSBs) are considered promising candidates for next-generation energy-storage systems due to their enhanced safety and high theoretical energy density. However, usually both solid-state electrolyte (SSE) and conductive carbon need to be incorporated into the cathode composite to provide Li+/electron pathways, leading to the reduced energy density and inevitable SSE decomposition. Moreover, the real electrochemical behavior of S or Li2S cathodes can not be reflected due to the partially overlapped redox reaction of SSE. Herein, a series of unique P4S10+n cathodes for high-performance ASSLSBs that totally do not need any extra SSE additives are reported. Synchrotron-based X-ray absorption near edge structure coupled with other analyses confirmed that ionic conductive Li3PS4 together with Li4P2S6 components can be electrochemically self-generated during lithiation process and partially maintained to provide fast Li+ transport pathways within the cathode layer. This is further evidenced by a 30–43-fold higher reversible capacity for P4S10+n/C cathodes compared to a S/C cathode. Bulk-type ASSLSBs based on the P4S34/C cathode show a highly reversible capacity of 883 ​mAh g−1 and stable cycling performance over 180 cycles with a high active material content of 70 ​wt%. The present study provides a promising approach for generating ionic conductive components from the electrode itself to facilitate Li+ migration within electrodes in ASSLSBs.

Kinetics of all-solid-state sulfur cathodes

All-solid-state lithium sulfur batteries (ASLSB) have many advantages over liquid electrolyte-based lithium sulfur batteries such as high sulfur utilization, low electrolyte-to-sulfur ratio and low self-discharge. However, the kinetics of all-solid-state sulfur cathodes is not well understood, which is critical to achieve their full potential. In this work, we determine the contributions of different processes to the overall kinetics of sulfur electrodes using Electrochemical Impedance Spectroscopy (EIS) and Gravimetric Intermittent Titration Technique (GITT). We show that the impedance of sulfur electrodes can be well described by the Transmission Line Model (TLM). It is found that the kinetics of the sulfur electrode is determined primarily by ionic migration at the electrode level and diffusion within the sulfur active materials. Based on this understanding, we compared kinetics of sulfur electrodes with different solid electrolytes and mixing methods. Electrodes using amorphous sulfide solid electrolyte and impregnated S/C composites display the best kinetics. ASLSB possess high capacities at moderate rates at room temperature, and can operate even at 120 ​°C. Combined with the negligible self-discharge over a year, we believe that ASLSB is a promising candidate for high-energy primary batteries.

Free-standing sulfide/polymer composite solid electrolyte membranes with high conductance for all-solid-state lithium batteries

Bulk-type all-solid-state lithium batteries (ASSLBs) with high theoretical capacity and good safety are considered to be promising candidates as future energy storage devices. The ASSLBs with inorganic electrolytes usually have a thick electrolyte layer (more than 1 mm), which significantly reduces the cell-based energy density; therefore, a free-standing high-conductance electrolyte layer with a low thickness is essential for high-performance ASSLBs. In this work, we prepare free-standing 78Li2S–22P2S5 glass-ceramic (7822gc) composite solid electrolyte membranes reinforced with polymer electrolytes with a thickness of 120 μm through a liquid-phase method and systematically investigate the effects of solvents and polymer electrolytes on the microstructure and electrochemical properties of the 7822gc/polymer composite membranes. The sulfide/PEO and sulfide/PVDF composite electrolytes without lithium salt show an ionic conductivity of 2–4 × 10−4 S cm−1 at room temperature, while the conductivity of those with lithium salt is enhanced to 4–7 × 10−4 S cm−1. With such a high conductivity and low thickness, an ultra-high areal conductance of 59.0 mS cm−2 is obtained for the composite electrolyte membranes, which is ~2.7 times of that of pure 7822gc electrolyte pellets. All-solid-state lithium-sulfur batteries (ASSLSBs) with a sulfur/carbon nanotube composite cathode and a Li–In alloy anode are prepared. The cell-based energy density is as high as 87.0 Ah L−1. A discharge capacity of 725.1 mA h g−1 at 0.176 mA cm−2 after 100 cycles and a high capacity retention of 93.2% are achieved for the cells with 7822gc/polymer composite electrolyte membranes.

Improved interfacial electronic contacts powering high sulfur utilization in all-solid-state lithium–sulfur batteries

All-solid-state lithium–sulfur batteries (ASSLSBs) afford a novel avenue for next-generation high energy density lithium–sulfur batteries due to the alleviated potential safety hazards. However, ASSLSBs suffer from high interfacial impedance and poor kinetics of electrochemical reactions. Herein, we probed the interfacial electron transfer between active sulfur and conductive carbon in a working cell. The co-axial carbon nanotube@sulfur composite with more robust electron contacts enables fast electron transportation and reduced interfacial charge transfer impedance, leading to a high sulfur utilization and excellent electrochemical performance. An initial discharge capacity of 1138.7 mAh g−1 at 0.21 mA cm−2 (0.1C) with a capacity retention of 87.7% after 200 cycles is achieved at a sulfur loading of 1.3 mg cm−2. Moreover, the cathode with superior and uniform electronic contacts delivers better rate capability and a higher discharge specific capacity at a high sulfur loading ranging from 3.8 to 5.9 mg cm−2. This work verifies the significance of 3D interconnected electronic pathways in the sulfur cathode for high performance ASSLSBs.

Solid/Solid Interfacial Architecturing of Solid Polymer Electrolyte-Based All-Solid-State Lithium-Sulfur Batteries by Atomic Layer Deposition.

Solid polymer electrolytes (SPEs)-based all-solid-state lithium-sulfur batteries (ASSLSBs) have attracted extensive research attention due to their high energy density and safe operation, which provide potential solutions to the increasing need for harnessing higher energy densities. There is little progress made, however, in the development of ASSLSBs to improve simultaneously energy density and long-term cycling life, mostly due to the "shuttle effect" of lithium polysulfide intermediates in the SPEs and the low interfacial compatibility between the metal lithium anode and the SPE. In this work, the issues of solid/solid interfacial architecturing through atomic layer deposition of Al2 O3 on poly(ethylene oxide)-lithium bis(trifluoromethanesulfonyl)imide SPE surface are effectively addressed. The Al2 O3 coating promotes the suppression of lithium dendrite formation for over 500 h. ASSLSBs fabricated with two layers of Al2 O3 -coated SPE deliver high gravimetric/areal capacity and Coulombic efficiency, as well as excellent cycling stability and extremely low self-discharge rate. This work provides not only a simple and effective approach to boost the electrochemical performances of SPE-based ASSLSBs, but also enriches the fundamental understanding regarding the underlying mechanism responsible for their performance.

High Capacity and Superior Cyclic Performances of All-Solid-State Lithium-Sulfur Batteries Enabled by a High-Conductivity Li10SnP2S12 Solid Electrolyte.

All-solid-state lithium-sulfur batteries (ASSLSBs) employing sulfide-based solid electrolytes have gained widespread attention for their high energy density and intrinsic safety. Li10SnP2S12 is identified as one of the most rivaling candidates in sulfide electrolytes. Herein, a highly Li-ion-conductive Li10SnP2S12 solid-state electrolyte (SSE) is synthesized via a combination of high-energy ball-milling and heat treatment processes, which is more facile and efficient compared with other previously reported methods. The obtained Li10SnP2S12 SSE exhibits high ionic conductivity (3.2 × 10-3 S cm-1) at room temperature (RT). The effects of the annealing temperature on the Li-ion conductivity and activation energy of Li10SnP2S12 are also thoroughly studied. Moreover, the ASSLSBs based on the Li10SnP2S12 electrolyte are constructed, and they deliver a high initial capacity of 1601.7 mAh g-1 at 40 mA g-1. A favorable capacity retention upon cycling and a good rate performance are also achieved at RT. Concomitantly, the Coulombic efficiency approaches 100% during the prolonged cycling. This work tremendously accelerates the practical applications of the Li10SnP2S12 SSE among the emerging high-energy ASSLSBs.

In Situ Generated Li2S-C Nanocomposite for High-Capacity and Long-Life All-Solid-State Lithium Sulfur Batteries with Ultrahigh Areal Mass Loading.

All-solid-state lithium-sulfur batteries (ASSLSBs) have attracted great attention due to their inherent ability to eliminate the two critical issues (polysulfide shuttle effect and safety) of traditional liquid electrolyte based Li-S batteries. However, it remains a huge challenge for ASSLSBs to achieve high areal active mass loading and high active material utilization simultaneously due to the insulating nature of sulfur and Li2S, and the large volume change during cycling. Herein, a Li2S@C nanocomposite with Li2S nanocrystals uniformly embedded in conductive carbon matrix, is in situ generated by the combustion of lithium metal with CS2. Benefiting from its unique architecture, the Li2S@C exhibits exceptional electrochemical performance as cathode for ASSLSBs, with both ultrahigh areal Li2S loading (7 mg cm-2) and 91% of Li2S utilization (corresponding to a reversible capacity of 1067 mAh g-1). Moreover, the Li2S@C also possesses outstanding rate capability and cycling stability. High reversible capacity of 644 mAh g-1 is delivered at 2 mA cm-2 even after 700 cycles. This work demonstrates that ASSLSBs with superior electrochemical performance can be realized via rational design of the cathode structure, which provides a promising prospect to the development of ASSLSBs with practical energy density surpassing that of lithium ion batteries.

High-Conductivity Argyrodite Li6PS5Cl Solid Electrolytes Prepared via Optimized Sintering Processes for All-Solid-State Lithium–Sulfur Batteries

Highly Li-ion conductive Li6PS5Cl solid-state electrolytes (SSEs) were prepared by solid-state sintering method. The influence of sintering temperature and duration on the phase, ionic conductivity, and activation energy of Li6PS5Cl was systematically investigated. The Li6PS5Cl electrolyte with a high ionic conductivity of 3.15 × 10-3 S cm-1 at room temperature (RT) was obtained by sintering at 550 °C for just 10 min, which was more efficient taking into account such a short preparation time in comparison with other reported methods to synthesize Li6PS5Cl SSEs. All-solid-state lithium sulfur batteries (ASSLSBs) based on the Li6PS5Cl SSE were assembled by using the nano-sulfur/multiwall carbon nanotube composite combined with Li6PS5Cl as the cathode and Li-In alloy as the anode. The cell delivered a high discharge capacity of 1850 mAh g-1 at RT for the first full cycle at 0.176 mA cm-2 (∼0.1C). The discharge capacity was 1393 mAh g-1 after 50 cycles. In addition, the Coulombic efficiency remained nearly 100% during galvanostatic cycling. The experimental data showed that Li6PS5Cl was a good candidate for the SSE used in ASSLSBs.

Understanding the Role of Nano‐Aluminum Oxide in All‐Solid‐State Lithium‐Sulfur Batteries

AbstractAluminum oxide (Al2O3) is a well‐known electrolyte filler for stabilizing the Li‐metal (Li0) anode in all‐solid‐state Li0‐based batteries. However, its strong interactions with lithium polysulfides (PS) hinder the direct application of Al2O3‐added electrolytes in all‐solid‐state lithium‐sulfur batteries (ASSLSBs). Herein, the role of Al2O3 in ASSLSBs both as electrolyte filler and cathode additive is studied. The combination of Al2O3‐added electrolyte and Al2O3‐added S8 cathode with optimum cell configuration could deliver an unprecedented discharge capacity of 0.85 mAh cm−2 (C/10, 30 cycles) for polymer‐based ASSLSBs. These results suggest that the rational incorporation of Al2O3 can lead simultaneously to PS anchoring and Li0 anode stabilizing benefits from the ceramic filler, thus improving the electrochemical performance of ASSLSBs.

Sulfide Based Solid Electrolyte for Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries have the potential to deliver higher energy at lower cost compared to state-of-the-art Li-ion batteries. Greatest obstacles for deployment of Li-S batteries lie in polysulfide dissolution/shuttle and high Electrolyte/sulfur ratio required for stable long term cycling. In all-solid-state Li-S batteries (ASSLiS), S conversion undergoes the solid-state route therefore excludes the problems of polysulfide dissolution and high E/S ratio. Sulfide-based solid electrolytes are most suitable for ASSLiS and excellent performance of S cathode has been demonstrated.1 Due to the insulating nature of S particles, short diffusion length is needed to realize high S utilization. Liquid phase synthesis of sulfide-based solid electrolyte has advantages of easy preparation of nanosized particle, great flexibility and tunability, better scalability, and thus is desired for sulfur electrode preparation. It was found in our study the crystalline Li7P3S11 forms through a two-step reaction: 1) formation of solid Li3PS4∙ACN and amorphous ‘Li2S∙P2S5’ phases in the liquid phase; 2) solid-state conversion of the two phases.2 The other significant obstacle of ASSLiS is lack of solid state electrolytes that support stable Li metal cycling at relevant current density and cycling depth. We developed a sulfide-based solid electrolyte that has extremely high ionic conductivity of 4.7 mS/cm and kinetically stable, low-impedance interface (< 10 Ω cm2) with Li metal anode. Long term Li/Li symmetric cell cycling was achieved at 0.5 mA/cm2. In addition, the material remains stable in structure and ionic conductivity within two hours exposure in the dry room environment. In this talk, we present our progress on the sulfide-based solid electrolytes for ASSLiS. References H. Nagata, Y. Chikusa. Journal of Power Sources 264 (2014) 206-210Y. Wang, D. Lu, Z Deng, J Xiao, J. Zhang and J. Liu. Chemistry of Materials 30 (3):990-997. doi:10.1021/acs.chemmater.7b04842

Ultrahigh Performance All Solid-State Lithium Sulfur Batteries: Salt Anion's Chemistry-Induced Anomalous Synergistic Effect.

With a remarkably higher theoretical energy density compared to lithium-ion batteries (LIBs) and abundance of elemental sulfur, lithium sulfur (Li-S) batteries have emerged as one of the most promising alternatives among all the post LIB technologies. In particular, the coupling of solid polymer electrolytes (SPEs) with the cell chemistry of Li-S batteries enables a safe and high-capacity electrochemical energy storage system, due to the better processability and less flammability of SPEs compared to liquid electrolytes. However, the practical deployment of all solid-state Li-S batteries (ASSLSBs) containing SPEs is largely hindered by the low accessibility of active materials and side reactions of soluble polysulfide species, resulting in a poor specific capacity and cyclability. In the present work, an ultrahigh performance of ASSLSBs is obtained via an anomalous synergistic effect between (fluorosulfonyl)(trifluoromethanesulfonyl)imide anions inherited from the design of lithium salts in SPEs and the polysulfide species formed during the cycling. The corresponding Li-S cells deliver high specific/areal capacity (1394 mAh gsulfur-1, 1.2 mAh cm-2), good Coulombic efficiency, and superior rate capability (∼800 mAh gsulfur-1 after 60 cycles). These results imply the importance of the molecular structure of lithium salts in ASSLSBs and pave a way for future development of safe and cost-effective Li-S batteries.

Lithium Azide as an Electrolyte Additive for All-Solid-State Lithium-Sulfur Batteries.

Of the various beyond-lithium-ion battery technologies, lithium-sulfur (Li-S) batteries have an appealing theoretical energy density and are being intensely investigated as next-generation rechargeable lithium-metal batteries. However, the stability of the lithium-metal (Li°) anode is among the most urgent challenges that need to be addressed to ensure the long-term stability of Li-S batteries. Herein, we report lithium azide (LiN3 ) as a novel electrolyte additive for all-solid-state Li-S batteries (ASSLSBs). It results in the formation of a thin, compact and highly conductive passivation layer on the Li° anode, thereby avoiding dendrite formation, and polysulfide shuttling. It greatly enhances the cycling performance, Coulombic and energy efficiencies of ASSLSBs, outperforming the state-of-the-art additive lithium nitrate (LiNO3 ).

Review—Solid Electrolytes for Safe and High Energy Density Lithium-Sulfur Batteries: Promises and Challenges

All-solid-state lithium-sulfur batteries (ASSLSBs) offer a means to enhance the energy density and safety of the state-of-art lithium-ion batteries (LIBs), due to their high gravimetric energy density, low cost and environmental benignancy. In this work, the status of the research advances and perspectives on several types of solid electrolytes (SEs) developed for ASSLSBs are reviewed. The promises and challenges of utilizing SEs are discussed taking into account both theoretical calculation and experimental results, in hope of shedding some lights on future design of high energy density, cost competitive, and safe Li-S batteries.

High-Performance All-Solid-State Lithium-Sulfur Battery Enabled by a Mixed-Conductive Li2S Nanocomposite.

All-solid-state lithium-sulfur batteries (ASSLSBs) using highly conductive sulfide-based solid electrolytes suffer from low sulfur utilization, poor cycle life, and low rate performance due to the huge volume change of the electrode and the poor electronic and ionic conductivities of S and Li2S. The most promising approach to mitigate these challenges lies in the fabrication of a sulfur nanocomposite electrode consisting of a homogeneous distribution of nanosized active material, solid electrolyte, and carbon. Here, we reported a novel bottom-up method to synthesize such a nanocomposite by dissolving Li2S as the active material, polyvinylpyrrolidone (PVP) as the carbon precursor, and Li6PS5Cl as the solid electrolyte in ethanol, followed by a coprecipitation and high-temperature carbonization process. Li2S active material and Li6PS5Cl solid electrolyte with a particle size of ∼4 nm were uniformly confined in a nanoscale carbon matrix. The homogeneous nanocomposite electrode consisting of different nanoparticles with distinct properties of lithium storage capability, mechanical reinforcement, and ionic and electronic conductivities enabled a mechanical robust and mixed conductive (ionic and electronic conductive) sulfur electrode for ASSLSB. A large reversible capacity of 830 mAh/g (71% utilization of Li2S) at 50 mA/g for 60 cycles with a high rate performance was achieved at room temperature even at a high loading of Li2S (∼3.6 mg/cm(2)). This work provides a new strategy to design a mechanically robust, mixed conductive nanocomposite electrode for high-performance all-solid-state lithium sulfur batteries.

All-Solid State Lithium-Sulfur Batteries

Currently, lithium-ion batteries incorporated in electric vehicles do not allow to store enough energy to ensure sufficient autonomy. Therefore, it’s necessary to develop new generations of batteries with higher energy density. Among battery technologies, the lithium-sulfur system (Li-S) is considered to be one of the most promising solutions due to a theoretical energy density of 2500 Wh/kg. However, its lifetime remains limited due to the polysulfide shuttle effect, induced by the use of liquid electrolyte. Indeed, many polysulfides (noted Li2Sx 1 ≤ x ≤ 8), formed during the sulfur reduction to Li2S, dissolve in liquid electrolyte and diffuse between both electrodes, leading to a rapid decrease of electrochemical performances. All-solid-state Li-S batteries were studied in order to bypass the limitations of liquid electrolyte. The electrode is a composite material with sulfur (S8) as active material, argyrodite (Li6PS5Cl) as solid electrolyte for ionic conduction and Ketjen Black (KB) as additive conductor for electronic percolation. The liquid electrolyte between both electrodes is replaced by the solid electrolyte used in the composite electrode and metallic lithium is used as negative electrode. /sub>Sx 1 ≤ x ≤ 8), formed during the sulfur reduction to Li2S, dissolve in liquid electrolyte and diffuse between both electrodes, leading to a rapid decrease of electrochemical performances. The positive electrode was prepared by mixing and ball-milling at 370 rpm for 5h using a high-energy planetary ball mill, S8, Li6PS5Cl and KB with a weight ratio of 25:50:25. The battery displays a reversible capacity of 1565 mAh/g after 10 cycles at a current density of 134 µA/cm² (corresponding to a rate of C/10) with an initial discharge capacity of 1230 mAh/g and an extra capacity of around 335 mAh/g, observed for the first time and currently under studies. 8), formed during the sulfur reduction to Li2S, dissolve in liquid electrolyte and diffuse between both electrodes, leading to a rapid decrease of electrochemical performances. At high current density, with lithium negative electrode, we observed strange potential decreases that can be related to short circuit phenomena. One explanation for short circuit phenomena can be the formation of lithium dendrites, although they are not supposed to grow in solid electrolyte. The presence of dendrites will be evidenced by solid state NMR. Using alternative Li-In electrode, this phenomenon was totally suppressed. In this presentation, we will then show our best optimized solid state batteries using a Li-Indium electrode with a good capacity (1660 mAh/g after 10 cycles at C/10), a good coulombic efficiency and a reasonable polarization for a solid-state battery and at room temperature. Perspectives in term of energy density and industrialization (upscale of the lithium ion conductors) will be presented.

Preparation of metastable rare earth sulphide by mechanical alloying and mechanical milling : S.H. Han et al. (Iowa State University, USA.) Scripta Metal. Mater., Vol 25, No 2, 1991, 295–298

All-solid-state lithium-sulfur batteries (ASSLSBs) employing sulfide solid electrolytes are one of the most promising next-generation energy storage systems due to their potential for higher energy density and safety. However, scalable fabrication of sheet-type sulfur cathodes with high sulfur loading and excellent performances remains challenging. In this work, sheet-type freestanding sulfur cathodes with high sulfur loading were fabricated by dry electrode technology. The unique fibrous morphologies of polytetrafluoroethylene (PTFE) binders in dry electrodes not only provides excellent mechanical properties but also uncompromised ionic/electronic conductance. Even employed with thickened dry cathodes with high sulfur loading of 2 mg cm−2, ASSLSBs still exhibit outstanding rate performance and cycle stability. Moreover, the all-solid-state lithium-sulfur monolayer pouch cells (9.2 mAh) were also demonstrated and exhibited excellent safety under a harsh test situation. This work verifies the potential of dry electrode technology in the scalable fabrication of thickened sulfur cathodes and will promote the practical applications of ASSLSBs.