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Since the first demonstration of prototype Li batteries (TiS 2 /Li) in 1976, [1] the develo pment of LIBs to date has been strongly affected by safety issues. One of the major technical breakthroughs for the commer cialization of LIBs was the replacement of Li metal with carbonaceous materials as the anode. [2][3][4] It is well known that the use of Li metal was challenged by serious safety concerns associated with internal short circuit by the dendritic growth of Li metal. [5][6][7] The everrising requirements for higher energy density of LIBs have raised more serious safety concerns. Raising the upper cutoff voltages leads to poorer sta bility at electrode-electrolyte interfaces. [8,9] Ultrathinning the polymeric separators to less than 10 µm, despite the reinforce ments using ceramic materials, [10][11][12] result in more vulnerability toward internal short circuits. These may also be related to degassing, fire, and explosion accidents of LIBs in recent years. Further more, largescale applications of LIBs, such as batterydriven electric vehicles and gridscale energy storages, face unprecedented challenges in terms of safety requirements. [13][14][15] In this regard, solidification of conventional flammable organic liquid electrolytes with inorganic materials, such as superionic conductor solid electrolytes (SEs), is an ideal solution. [16][17][18][19][20][21][22][23][24][25] Another strong motivation in the development of SEs is to unleash the harness of limited energy density for con ventional LIBs by using SEs to stabilize and enable alternative highcapacity electrode materials, such as Li metal anode and sulfur cathode. [15,23] Additionally, the design of allsolidstate Li or Liion batteries (ALSBs) by stacking bipolar electrodes allows the minimization of inactive encasing materials, thereby increasing celllevel energy density. [22,26] The first superionic conductors PbF 2 and Ag 2 S were discov ered by Michael Faraday in 1838. [27] Since then, several notable progresses in the field of solidstate superionic conductors and their newly enabled electrochemical devices had occurred; [27] the development of oxygenion conductors (Ydoped ZrO 2 ) applied to solid oxide fuel cells, the discoveries of Ag + superionic conduc tors (e.g., RbAg 4 I 5 ), and the development of Naion conducting sodium beta alumina (β″Al 2 O 3 ). Currently, it is a promi sing opportunity for Liion SEs to revolutionize LIB technologies Owing to the ever-increasing safety concerns about conventional lithium-ion batteries, whose applications have expanded to include electric vehicles and grid-scale energy storage, batteries with solidified electrolytes that utilize nonflammable inorganic materials are attracting considerable attention. In particular, owing to their superionic conductivities (as high as ≈10 −2 S cm −1 ) and deformability, sulfide materials as the solid electrolytes (SEs) are considered the enabling material for high-energy bulk-type all-solid-state batteries. Herein the authors provide a brief review on recent progress in sulf...

Bulk-type all-solid-state lithium-ion batteries (ASLBs) have the potential to be superior to conventional lithium-ion batteries (LIBs) in terms of safety and energy density. Sulfide SE materials are key to the development of bulk-type ASLBs because of their high ionic conductivity (max of ∼10 S cm) and deformability. However, the severe reactivity of sulfide materials toward common polar solvents and the particulate nature of these electrolytes pose serious complications for the wet-slurry process used to fabricate ASLB electrodes, such as the availability of solvent and polymeric binders and the formation of ionic contacts and networks. In this work, we report a new scalable fabrication protocol for ASLB electrodes using conventional composite LIB electrodes and homogeneous SE solutions (LiPSCl (LPSCl) in ethanol or 0.4LiI-0.6LiSnS in methanol). The liquefied LPSCl is infiltrated into the tortuous porous structures of LIB electrodes and solidified, providing intimate ionic contacts and favorable ionic percolation. The LPSCl-infiltrated LiCoO and graphite electrodes show high reversible capacities (141 and 364 mA h g) at 0.14 mA cm (0.1 C) and 30 °C, which are not only superior to those for conventional dry-mixed and slurry-mixed ASLB electrodes but also comparable to those for liquid electrolyte cells. Good electrochemical performance of ASLBs employing the LPSCl-infiltrated LiCoO and graphite electrodes at 100 °C is also presented, highlighting the excellent thermal stability and safety of ASLBs.

A new, highly conductive (4.1 × 10(-4) S cm(-1) at 30 °C), highly deformable, and dry-air-stable glass 0.4LiI-0.6Li4 SnS4 is prepared using a homogeneous methanol solution. The solution process enables the wetting of any exposed surface of the active materials with highly conductive solidified electrolytes (0.4LiI-0.6Li4 SnS4), resulting in considerable improvements in the electrochemical performance of these electrodes over conventional mixture electrodes.

Bulk-type all-solid-state lithium batteries (ASLBs) are considered a promising candidate to outperform the conventional lithium-ion batteries. Unfortunately, the current technology level of ASLBs is in a stage of infancy in terms of cell-based (not electrode-material-based) energy densities and scalable fabrication. Here, we report on the first ever bendable and thin sulfide solid electrolyte films reinforced with a mechanically compliant poly(paraphenylene terephthalamide) nonwoven (NW) scaffold, which enables the fabrication of free-standing and stackable ASLBs with high energy density and high rate capabilities. The ASLB, using a thin (∼70 μm) NW-reinforced SE film, exhibits a 3-fold increase of the cell-energy-density compared to that of a conventional cell without the NW scaffold.

For all‐solution‐processed (ASP) devices, transparent conducting oxide (TCO) nanocrystal (NC) inks are anticipated as the next‐generation electrodes to replace both those synthesized by sputtering techniques and those consisting of rare metals, but a universal and one‐pot method to prepare these inks is still lacking. A universal one‐pot strategy is now described; through simply heating a mixture of metal–organic precursors a wide range of TCO NC inks, which can be assembled into high‐performance electrodes for use in ASP optoelectronics, were synthesized. This method can be used for various oxide NC inks with yields as high as 10 g. The formed NCs are of high crystallinity, uniform morphology, monodispersity, and high ink stability and feature effective doping. Therefore, the inks can be readily assembled into films with a surface roughness of 1.6 nm. Typically, a sheet resistance of 110 Ω sq−1 can be achieved with a transmittance of 88 %, which is the best performance for TCO NC ink‐based electrodes described to date. These electrodes can thus drive a polymer light‐emitting diode (PLED) with a luminance of 2200 cd m−2 at 100 mA cm−2.

Most inorganic solid electrolytes (SEs) suffer from narrow intrinsic electrochemical windows and incompatibility with electrode materials, which results in the below par electrochemical performances of all-solid-state Li-ion or Li batteries (ASLBs). Unfortunately, in-depth understanding on the interfacial evolution and interfacial engineering via scalable protocols for ASLBs to mitigate these issues are at an infancy stage. Herein, we report on rationally designed Li3BO3–Li2CO3 (LBO-LCO or Li3–x B1–x C x O3 (LBCO)) coatings for LiCoO2 in ASLBs employing sulfide SE of Li6PS5Cl. The new aqueous-solution-based LBO-coating protocol allows us to convert the surface impurity on LiCoO2 and Li2CO3, into highly Li+-conductive LBCO layers (6.0 × 10–7 S cm–1 at 30 °C for LBCO vs 1.4 × 10–9 S cm–1 at 100 °C for Li2CO3 or 1.4 × 10–9 S cm–1 at 30 °C for LBO), which also offer interfacial stability with sulfide SE. By applying these high-surface-coverage LBCO coatings, significantly enhanced electrochemical performances are obtained in terms of capacity, rate capability, and durability. It is elucidated that the LBCO coatings suppress the evolution of detrimental mixed conducting interphases containing Co3S4 and effectively passivate the interfaces by the formation of alternative interface phases.

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