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Despite the enormous interest in high-areal-capacity Li battery electrodes, their structural instability and nonuniform charge transfer have plagued practical application. Herein, we present a cationic semi-interpenetrating polymer network (c-IPN) binder strategy, with a focus on the regulation of electrostatic phenomena in electrodes. Compared to conventional neutral linear binders, the c-IPN suppresses solvent-drying-induced crack evolution of electrodes and improves the dispersion state of electrode components owing to its surface charge-driven electrostatic repulsion and mechanical toughness. The c-IPN immobilizes anions of liquid electrolytes inside the electrodes via electrostatic attraction, thereby facilitating Li+ conduction and forming stable cathode–electrolyte interphases. Consequently, the c-IPN enables high-areal-capacity (up to 20 mAh cm–2) cathodes with decent cyclability (capacity retention after 100 cycles = 82%) using commercial slurry-cast electrode fabrication, while fully utilizing the theoretical specific capacity of LiNi0.8Co0.1Mn0.1O2. Further, coupling of the c-IPN cathodes with Li-metal anodes yields double-stacked pouch-type cells with high energy content at 25 °C (376 Wh kgcell−1/1043 Wh Lcell–1, estimated including packaging substances), demonstrating practical viability of the c-IPN binder for scalable high-areal-capacity electrodes. Binders employed in battery electrodes are conventionally neutral linear polymers. Here, authors present a cationic semi-interpenetrating polymer network binder to regulate electrostatic phenomena, improving the properties and performance of high-capacity positive electrodes for Li metal batteries. [ABSTRACT FROM AUTHOR]

Despite their potential as high‐energy‐density lithium battery electrodes, Li metals are still far from practical use mainly due to their insufficient electrochemical reliability. Here, a cholesteric liquid crystalline (cLC) cellulose nanocrystal (CNC) nanomembrane as a natural material‐based mechanically robust and precisely defined ion channel strategy for sustainable Li metal electrodes is demonstrated. The cLC‐CNC nanomembrane (1 µm) is designed to achieve a self‐assembled ordered nanoporous structure with optimal tortuosity. This well‐defined cLC structure and high mechanical modulus of CNC, which are difficult to attain with traditional synthetic materials, allow facile/uniform Li‐ion flux toward Li metal electrodes, and simultaneously prevent Li dendrite growth and mitigate volume expansion of the Li metal during Li plating/stripping cycling. Driven by these viable roles of the cLC‐CNC nanomembrane, Li metal full cells (consisting of thin Li metal anodes (20 µm) and high‐capacity LiNi0.8Co0.1Mn0.1O2 (NCM811) cathodes (3.8 mAh cm–2), capacity excess of the Li metal over the NCM811 = 1.0) exhibit high energy density (890 Wh Lcell–1) along with stable cycling retention, which lie far beyond those achievable with previously reported Li protective layers. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) have attracted considerable attention as a facile and versatile design platform for advanced energy storage materials owing to their structural diversity, ordered porous structures, and chemical stability. In this study, a redox‐active COF (TP–OH–COF) that can accommodate 30 Li+ ions is synthesized for potential use as an ultralong cyclable high‐capacity lithium‐ion battery electrode material. The TP–OH–COF is synthesized using triformylpholoroglucinol and 2,5‐diaminohydroquinone dihydrochloride under solvothermal conditions. The accommodation of such exceptional Li+ ion content in the TP–OH–COF is achieved by alternately tethering redox‐active hydroxyl and carbonyl sites on the pore walls. Owing to this unique chemical/structural feature, the TP–OH–COF delivers a high specific capacity of 764.1 mAh g–1, and capacity retention of 63% after 8000 cycles at a fast current density of 5.0 A g–1. [ABSTRACT FROM AUTHOR]

Despite the ever‐growing demand for Li metals as next‐generation Li battery electrodes, little attention has been paid to their oxidation stability, which must be achieved for practical applications. Here, a new class of printable solid electrolyte interphase mimic (pSEI) for antioxidative Li metal electrodes is presented. The pSEI (≈1 µm) is directly fabricated on a thin Li metal electrode (25 µm) by processing solvent‐free, UV polymerization‐assisted printing, exhibiting its manufacturing simplicity and scalability. The pSEI is rationally designed to mimic a typical SEI comprising organic and inorganic components, in which ethoxylated trimethylolpropane triacrylate and diallyldimethylammonium bis(trifluoromethanesulfonyl)imide are introduced as an organic mimic (acting as a moisture‐repellent structural framework) and inorganic mimic (allowing facile Li‐ion transport/high Li+ transference number), respectively. Driven by the chemical/architectural uniqueness, the pSEI enables the thin Li metal electrode to show exceptional antioxidation stability and reliable full cell performance after exposure to humid environments. [ABSTRACT FROM AUTHOR]

Despite extensive research on flexible/wearable power sources, their structural stability and electrochemical reliability upon mechanical deformation and charge/discharge cycling have not yet been completely achieved. A new class of galvanically replaced single‐bodied lithium‐ion battery (LIB) fabric electrodes is demonstrated. As a proof of concept, metallic tin (Sn) is chosen as an electrode active material. Mechanically compliable polyethyleneterephthalate (PET) fabrics are conformally coated with thin metallic nickel (Ni) layers via electroless plating to develop flexible current collectors. Driven by the electrochemical potential difference between Ni and Sn, the thin Ni layers are galvanically replaced with Sn, resulting in the fabrication of a single‐bodied Sn@Ni fabric electrode (Sn is monolithically embedded in the Ni matrix on the PET fabric). Benefiting from the chemical/structural uniqueness and rationally designed bicontinuous ion/electron transport pathways, the single‐bodied Sn@Ni fabric electrode provides exceptional redox reaction kinetics and omnidirectional deformability (notably, origami‐folding boats), which lie far beyond those attainable with conventional LIB electrode technologies. [ABSTRACT FROM AUTHOR]

The effect of the O3 feeding time on the physical and electrical properties of TiO2 thin films on Ru electrodes was investigated. The density, composition, chemical state, and crystalline structure of the TiO2 films were almost identical, irrespective of the O3 feeding time, even when the TiO2 films were grown under subsaturated conditions with respect to the O3 feeding. However, increasing the O3 feeding time to more than 3 s brought about surface roughening and severe local protrusion of the films, which significantly increased their leakage current density. The conduction band offset of the film surface was generally small and was not increased by increasing the O3 feeding time nor was the leakage current improved. Consequently, a minimum tox of 0.8 nm with a leakage current density <∼1×10-7 A/cm2 at an applied voltage of 0.8 V was achieved at an O3 feeding time of 2–3 s. [ABSTRACT FROM AUTHOR]

The ongoing surge in demand for high-energy/flexible rechargeable batteries relentlessly drives technological innovations in cell architecture as well as electrochemically active materials. Here, a new class of all-nanomat lithium-ion batteries (LIBs) based on 1D building element-interweaved heteronanomat skeletons is demonstrated. Among various electrode materials, silicon (Si, for anode) and overlithiated layered oxide (OLO, for cathode) materials are chosen as model systems to explore feasibility of this new cell architecture and achieve unprecedented cell capacity. Nanomat electrodes, which are completely different from conventional slurry-cast electrodes, are fabricated through concurrent electrospinning (for polymeric nanofibers) and electrospraying (for electrode materials/carbon nanotubes (CNTs)). Si (or rambutan-shaped OLO/CNT composite) powders are compactly embedded in the spatially interweaved polymeric nanofiber/CNT heteromat skeletons that play a crucial role in constructing 3D-bicontinuous ion/electron transport pathways and allow for removal of metallic foil current collectors. The nanomat Si anodes and nanomat OLO cathodes are assembled with nanomat Al2O3 separators, leading to the fabrication of all-nanomat LIB full cells. Driven by the aforementioned structural/chemical uniqueness, the all-nanomat full cell shows exceptional improvement in electrochemical performance (notably, cell-based gravimetric energy density = 479 W h kgCell−1) and also mechanical deformability, which lie far beyond those achievable with conventional LIB technologies. [ABSTRACT FROM AUTHOR]

Battery separators are supposed to be electrical insulators to prevent internal short-circuit failure between electrodes as well as having porous channels to allow ion transport. Here, as a multifunctional membrane strategy to dispel this stereotypical belief about battery separators, a new class of Janus-faced, dual (ion/electron)-conductive/chemically active battery separators (denoted as 'Janus separators') based on a heterolayered nanofiber mat architecture is demonstrated. The Janus separator, which is fabricated through in-series, concurrent electrospraying/electrospinning processes, consists of an ion-conductive/metal ion-chelating support layer (a mat of densely packed, thiol-functionalized silica particles spatially besieged by polyvinylpyrrolidone/polyacrylonitrile nanofibers) and a dual-conductive top layer (a thin mat of polyetherimide nanofibers wrapped with multi-walled carbon nanotubes). The support layer acts as a chemical trap that can capture heavy metal ions dissolved in liquid electrolytes and the top layer serves as an upper current collector for cathodes to boost the redox reaction kinetics. Notably, the unusual porous microstructure of the top layer is theoretically elucidated using molecular dynamics simulation. Benefiting from such material/structural uniqueness, the Janus separator enables significant improvements in fast-rate charge/discharge reactions (even for high-mass loading cathodes) and in the high-temperature cycling performance, which lie far beyond those achievable with conventional polyethylene separators. [ABSTRACT FROM AUTHOR]

Acquisition of high-energy density is the highest priority requirement and unending challenge in energy storage systems including lithium-ion batteries (LIBs). One theoretically preferable way to reach this goal is the use of cathode active materials such as vanadium pentoxide (V2O5) that relies on multielectron insertion/extraction reactions. Application of V2O5 to LIB cathodes, however, has been mostly focused on V2O5 materials themselves with little emphasis on V2O5-incorporated cathode sheets. Here, as an unusual electrode-architecture approach to achieve ultrahigh-capacity V2O5 cathode sheets, a new class of self-standing V2O5 cathode sheets is demonstrated based on V2O5/multiwalled carbon tubes (MWNTs) mixtures spatially besieged by polyacrylonitrile nanofibers (referred to as 'VMP cathode sheets'). Notably, the VMP cathode sheet is fabricated directly via one-pot synthetic route starting from V2O5 precursor (i.e., through concurrent electrospraying/electrospinning followed by calcination), without metallic foil current collectors/carbon powders/polymeric binders. The one-pot synthesis allows dense packing of V2O5 nanoparticles in close contact with MWNT electronic networks and also formation of well-developed interstitial void channels (ensuring good electrolyte accessibility). This material/architecture uniqueness of the VMP cathode sheet eventually enables significant improvements in cell performance (particularly, gravimetric/volumetric capacity of cathode sheets) far beyond those accessible with conventional electrode technologies. [ABSTRACT FROM AUTHOR]

The cathode active particles‐embedded polyacrylonitrile nanofibers/multiwalled carbon nanotubes heteronanomat cathode (HM cathode) is demonstrated as an effective and versatile electrode platform to address the long‐standing challenges of conventional cathodes. The material/structure uniqueness of the HM cathode enables substantial improvements in rate capability, cycling performance and, most notably, areal capacity far beyond those accessible with conventional cathode technologies. [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]

Abstract: A unique approach for improving the thermal stability of LiCoO2 cathode is presented, which is based on the treatment of LiCoO2 with ionic liquid (BDMIPF6, butyldimethylimidazolium-hexafluorophosphate), instead of traditional electrolyte modification. The electrolyte modification by the BDMIPF6 addition deteriorates the C-rate performances especially at high charge/discharge rates, with slightly improving the exothermic reaction between delithiated (charged) LiCoO2 and electrolytes. On the other hand, the BDMIPF6-modified cathode noticeably improves the thermal stability as well as little changes the C-rate performances. This is believed mainly due to the preferential location of BDMIPF6 in the LiCoO2 cathode rather than in the carbon anode, which might make it possible that the BDMIPF6 could effectively contribute to the suppression of exothermic reaction of delithiated LiCoO2 with electrolytes, with little affecting the electrolyte and the carbon anode. [Copyright &y& Elsevier]

Solid Electrolyte Interphases: Printable Solid Electrolyte Interphase Mimic for Antioxidative Lithium Metal Electrodes (Adv. Funct. Driven by the unique chemical structure and energy density-favorable dimensional design, the pSEI enables a thin Li metal electrode to show exceptional anti-oxidation stability and reliable full cell performance after exposure to humid environments. Antioxidation, humid environments, lithium metal electrodes, printing, solid electrolyte interphase mimic. [Extracted from the article]

Galvanic Replacement: Galvanically Replaced, Single-Bodied Lithium-Ion Battery Fabric Electrodes (Adv. Funct. Keywords: fabric electrodes; flexible electronics; galvanic replacement; lithium-ion batteries; redox kinetics EN fabric electrodes flexible electronics galvanic replacement lithium-ion batteries redox kinetics 1 1 1 04/22/20 20200420 NES 200420 In article number 1908633, Jae-Hun Kim, Sang-Young Lee, and co-workers present a galvanically replaced single-bodied Sn@Ni fabric electrode as a new approach for developing high-performance lithium-ion battery (LIB) electrodes with exceptional redox reaction kinetics and omnidirectional deformability. Fabric electrodes, flexible electronics, galvanic replacement, lithium-ion batteries, redox kinetics. [Extracted from the article]

Bulk‐type all‐solid‐state lithium batteries are highly promising candidates for large scale energy storage applications because of their superior safety. In article 1500865, Yoon Seok Jung and co‐workers demonstrate a strategy to obtain a dramatically improved performance by ensuring favorable ionic contacts. This is acheived via the addition of a small amount of solvate ionic liquids (Li(G3)TFSI), which demonstrate excellent compatibility with the sulfide solid electrolyte in composite electrodes. [ABSTRACT FROM AUTHOR]