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All‐solid‐state lithium‐ion batteries (ASLBs) employing sulfide solid electrolytes are attractive next‐generation rechargeable batteries that could offer improved safety and energy density. Recently, wet syntheses or processes for sulfide solid electrolyte materials have opened opportunities to explore new materials and practical fabrication methods for ASLBs. A new wet‐chemical route for the synthesis of Li‐deficient Li3−xPS4 (0≤x≤0.3) has been developed, which is enabled by dual solvents. Owing to its miscibility with tetrahydrofuran and ability to dissolve elemental sulfur, o‐xylene as a cosolvent facilitates the wet‐chemical synthesis of Li3−xPS4. Li3−xPS4 (0≤x≤0.15) derived by using dual solvents shows Li+ conductivity of approximately 0.2 mS cm−1 at 30 °C, in contrast to 0.034 mS cm−1 for a sample obtained by using a conventional single solvent (tetrahydrofuran, x=0.15). The evolution of the structure for Li3−xPS4 is also investigated by complementary analysis using X‐ray diffraction, Raman, and X‐ray photoelectron spectroscopy measurements. LiCoO2/Li–In ASLBs employing Li2.85PS4 obtained by using dual solvents exhibit a reversible capacity of 130 mA h g−1 with good cycle retention at 30 °C, outperforming cells with Li2.85PS4 obtained by using a conventional single solvent. [ABSTRACT FROM AUTHOR]

An unprecedentedly high electronic conductivity of 0.27 S cm −1 is achieved by depositing 0.56 wt% crystalline RuO 2 on LNMO via a wet-chemical route. Systematic assessment of the electrochemical performance of bare and RuO 2 -coated LNMO electrodes unambiguously demonstrates that the high electronic conductivity of RuO 2 enables significant enhancement in rate capability. These improvements are dramatic for the electrodes in which extremely low amounts of carbon additives are included and/or the loading amount is high. This finding highlights the importance of electronic conduction in composite electrodes, not only for high power but also for high energy density. The RuO 2 -coated LNMO electrode with 1 wt% carbon additives exhibits a high capacity of 100 mA h g −1 at 1C in the range 3.0–5.0 V (vs. Li/Li + ). This result is in sharp contrast to the negligible capacity exhibited by the bare LNMO electrode. In addition, the chemical/electrochemical stability of the RuO 2 coating under repeated cycling is confirmed, explaining the observed improvement in durability of the RuO 2 -coated LNMO over the bare LNMO. [ABSTRACT FROM AUTHOR]

The excellent stability of sulfide solid electrolytes with solvate ionic liquids Li(triethylene glycol dimethyl ether)bis(trifluoromethanesulfonyl)imide (Li(G3)TFSI), and their application for high‐performance, all‐solid‐state lithium‐ion batteries are successfully demonstrated. The addition of a small amount of Li(G3)TFSI gives an alternative ionic pathway through normally poor solid–solid contacts, leading to a dramatic increase in LiFePO4 composite electrode capacity. [ABSTRACT FROM AUTHOR]

For mass production of all‐solid‐state lithium‐ion batteries (ASLBs) employing highly Li+ conductive and mechanically sinterable sulfide solid electrolytes (SEs), the wet‐slurry process is imperative. Unfortunately, the poor chemical stability of sulfide SEs severely restrict available candidates for solvents and in turn polymeric binders. Moreover, the binders interrupt Li+‐ionic contacts at interfaces, resulting in the below par electrochemical performance. In this work, a new scalable slurry fabrication protocol for sheet‐type ASLB electrodes made of Li+‐conductive polymeric binders is reported. The use of intermediate‐polarity solvent (e.g., dibromomethane) for the slurry allows for accommodating Li6PS5Cl and solvate‐ionic‐liquid‐based polymeric binders (NBR‐Li(G3)TFSI, NBR: nitrile−butadiene rubber, G3: triethylene glycol dimethyl ether, LiTFSI: lithium bis(trifluoromethanesulfonyl)imide) together without suffering from undesirable side reactions or phase separation. The LiNi0.6Co0.2Mn0.2O2 and Li4Ti5O12 electrodes employing NBR‐Li(G3)TFSI show high capacities of 174 and 160 mA h g−1 at 30 °C, respectively, which are far superior to those using conventional NBR (144 and 76 mA h g−1). Moreover, high areal capacity of 7.4 mA h cm−2 is highlighted for the LiNi0.7Co0.15Mn0.15O2 electrodes with ultrahigh mass loading of 45 mg cm−2. The facilitated Li+‐ionic contacts at interfaces paved by NBR‐Li(G3)TFSI are evidenced by the complementary analysis from electrochemical and 7Li nuclear magnetic resonance measurements. [ABSTRACT FROM AUTHOR]

Owing to their potential for greater safety, higher energy density, and scalable fabrication, bulk-type all-solid-state lithium-ion batteries (ASLBs) employing deformable sulfide superionic conductors are considered highly promising for applications in battery electric vehicles. While fabrication of sheet-type electrodes is imperative from the practical point of view, reports on relevant research are scarce. This might be attributable to issues that complicate the slurry-based fabrication process and/or issues with ionic contacts and percolation. In this work, we systematically investigate the electrochemical performance of conventional dry-mixed electrodes and wet-slurry fabricated electrodes for ASLBs, by varying the different fractions of solid electrolytes and the mass loading. This information calls for a need to develop well-designed electrodes with better ionic contacts and to improve the ionic conductivity of solid electrolytes. As a scalable proof-of-concept to achieve better ionic contacts, a premixing process for active materials and solid electrolytes is demonstrated to significantly improve electrochemical performance. Pouch-type 80 × 60 mm 2 all-solid-state LiNi 0 · 6 Co 0 · 2 Mn 0 · 2 O 2 /graphite full-cells fabricated by the slurry process show high cell-based energy density (184 W h kg −1 and 432 W h L −1 ). For the first time, their excellent safety is also demonstrated by simple tests (cutting with scissors and heating at 110 °C). [ABSTRACT FROM AUTHOR]