Challenges in the commercialization of all solid-state and next-generation batteries including strategies, key points, and application of solid-state batteries.

Instead of commercial lithium-ion batteries (LIBs) using organic liquid electrolytes, all-solid-state lithium-ion batteries (ASSBs) employing solid electrolytes (SEs) are promising for applications in high-energy–density power applications and electric vehicles due to their potential for improving safety and achieving high capacity. Although remarkable progress in SEs has been achieved and has resulted in high ionic conductivity, which now reaches values comparable to those of liquid electrolytes, the typical use of a slurry process for the fabrication of conventional ASSBs inevitably causes harmful reactions between sulfide materials and polar solvents. Here, we studied the efficient infiltration process of SE slurry into conventional composite LIB electrodes (NCM622) for achieving high-energy-density ASSBs via a scalable solution-based fabrication process. Two methods are proposed to ensure that SE materials are evenly distributed and sufficiently infiltrated into the porous structures of LIB electrodes. The LPSCl SE solutions were effectively infiltrated into the electrodes at higher processing temperatures and the temperature was subsequently optimized at above the boiling point of the ethanol solvent due to the dynamic motion of SE molecules via a convective flow during solvent vaporization. Moreover, the porous LIB composite electrodes with a mixture of active materials of different particle sizes formed and filled capillary pores resulting in a high electrode density. The LPSCl SE-infiltrated NCM622 electrodes that used this strategy could remarkably improve the initial discharge capacity of ASSBs to as high as 177 mAh/g. These ASSBs also showed excellent performance even at high loading values (about 17 mg/cm²), making them competitive with LIBs using conventional liquid electrolytes.

Lithium–sulfur (Li‐S) batteries represent a promising solution for achieving high energy densities exceeding 500 Wh kg⁻¹, leveraging cathode materials with theoretical energy densities up to 2600 Wh kg⁻¹. These batteries are also cost‐effective, abundant, and environment‐friendly. In this study, an innovative approach is proposed utilizing highly oxidized single‐walled carbon nanotubes (Ox‐SWCNTs) as a conductive fibrous scaffold and functional interlayer in sulfur cathodes and separators, respectively, to demonstrate large‐area and ultra‐flexible Li‐S batteries with enhanced energy density. The free‐standing sulfur cathodes in the Li‐S cells exhibit high energy density maintaining 806 mAh g⁻¹ even after 100 charge‐discharge cycles. Additionally, oxygen‐containing functional groups on the SWCNTs significantly improve electrochemical performance by promoting the adsorption of lithium polysulfides. Employing Ox‐SWCNTs in both cathodes and interlayers, the study achieves high‐capacity Li‐S pouch cells that consistently deliver a capacity of 1.06 Ah and a high energy density of 909 mAh g⁻¹ over 50 charge‐discharge cycles. This strategy not only significantly enhances the electrochemical performance of Li‐S batteries but also maintains excellent mechanical flexibility under severe deformation, positioning this Ox‐SWCNT‐based architecture as a viable, light‐weight, and ultra‐flexible energy storage solution suitable for commercializing rechargeable Li‐S batteries.

Argyrodites, Li₆PS₅Cl (LPSCl), are considered one of the most promising solid electrolytes (SEs) for all-solid-state batteries (ASSBs). However, the use of petrochemical-based toxic solvents, such as dimethylformamide and tetrahydrofuran (THF), has limited their commercial applications in the mass production of SEs via liquid-phase synthesis both in the laboratory and industry. Herein, we aim to achieve the scalable production of cost-effective LPSCl-based sulfide SEs with high ionic conductivities (>2 mS cm⁻¹) based on various green and sustainable inert solvents. Our simple liquid-phase synthesis route was designed by using sulfur to form an intermediate polysulfide to completely dissolve precursors in common organic solvents without employing high-energy and high-pressure processes. Metastable polysulfides have high solubility in a broad range of solvents; they offer the use of greener and/or sustainable alternatives. The ASSBs fabricated with the LPSCl SEs using green solvents exhibited excellent electrochemical performance comparable to that of LPSCl wet-synthesized using conventional THF. LPSCl SEs fabricated using monoglyme, which has the most similar solvent properties to those of THF, exhibited the best ionic conductivity and contributed to the high electrochemical performance of ASSBs. The state-of-the-art bulk-type production of sulfide SEs using solution-phase synthesis should ultimately be replaced by green and/or sustainable solvents to reduce chemical-related effects on human health and eliminate environmental pollution. Therefore, this study will be of great interest to those who wish to mass-produce sulfide-based SEs cost-effectively for commercial applications with minimal unnecessary steps.