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NiCl2 with high theoretical voltage and thermal decomposition temperature attracts much attention as cathode material for thermal batteries with the requirement of high power density, high energy density and long work time. Unfortunately, the practical utilization of thermal batteries with NiCl2 cathode is limited by their poor electrochemical performance under large current, even with the conventional LiF-LiCl-LiBr all-lithium molten salt electrolyte which proposes ultrahigh lithium ion conductivity. In this work, an unexpected ionic exchange reaction between NiCl2 and LiBr in LiF-LiCl-LiBr was found, which would be the main reason for the poor electrochemical behavior of thermal batteries with NiCl2 cathode and LiF-LiCl-LiBr molten salt. On this basis, LiF-LiCl-Li2SO4, another all-lithium molten salt free of LiBr, was investigated as the new electrolyte for NiCl2 cathode. For the single cell of Li(Si)/LiF-LiCl-Li2SO4/NiCl2, a discharge capacity of 377 mA h g−1 (with a cut-off voltage of 1.2 V) was achieved with large current density (500 mA cm−2) applied at 520°C, which is almost twice of that of Li(Si)/LiF-LiCl-LiBr/NiCl2(190 mA h g−1) at the same conditions.

Ceramics are an important class of materials with widespread applications because of their high thermal, mechanical, and chemical stability. Computational predictions based on first principles methods can be a valuable tool in accelerating materials discovery to develop improved ceramics. It is essential to experimentally confirm the material properties of such predictions. However, materials screening rates are limited by the long processing times and the poor compositional control from volatile element loss in conventional ceramic sintering techniques. To overcome these limitations, we developed an ultrafast high-temperature sintering (UHS) process for the fabrication of ceramic materials by radiative heating under an inert atmosphere. We provide several examples of the UHS process to demonstrate its potential utility and applications, including advancements in solid-state electrolytes, multicomponent structures, and high-throughput materials screening.

The ionic conductivity of composite solid-state electrolytes does not meet the application requirements of solid-state lithium (Li) metal batteries owing to the harsh space charge layer of different phases and low concentration of movable Li + . Herein, we propose a robust strategy for creating high-throughput Li + transport pathways by coupling the ceramic dielectric and electrolyte to overcome the low ionic conductivity challenge of composite solid-state electrolytes. A highly conductive and dielectric composite solid-state electrolyte is constructed by compositing the poly(vinylidene difluoride) matrix and the BaTiO 3 –Li 0.33 La 0.56 TiO 3– x nanowires with a side-by-side heterojunction structure (PVBL). The polarized dielectric BaTiO 3 greatly promotes the dissociation of Li salt to produce more movable Li + , which locally and spontaneously transfers across the interface to coupled Li 0.33 La 0.56 TiO 3– x for highly efficient transport. The BaTiO 3 –Li 0.33 La 0.56 TiO 3– x effectively restrains the formation of the space charge layer with poly(vinylidene difluoride). These coupling effects contribute to a quite high ionic conductivity (8.2 × 10 −4  S cm −1 ) and lithium transference number (0.57) of the PVBL at 25 °C. The PVBL also homogenizes the interfacial electric field with electrodes. The LiNi 0.8 Co 0.1 Mn 0.1 O 2 /PVBL/Li solid-state batteries stably cycle 1,500 times at a current density of 180 mA g − 1 , and pouch batteries also exhibit an excellent electrochemical and safety performance. The authors developed a highly conductive and dielectric composite solid-state electrolyte by coupling BaTiO 3 and Li 0.33 La 0.56 TiO 3– x nanowires with a side-by-side heterojunction structure in a polyvinylidene difluoride matrix, which simultaneously promotes the dissociation of lithium salts to produce more movable Li ions and efficiently transports the generated movable Li ions.

To enable the development of all-solid-state batteries, an inorganic solid-state electrolyte should demonstrate high ionic conductivity (i.e., > 1 mS cm −1 at 25 °C), compressibility (e.g., > 90% density under 250−350 MPa), and cost-effectiveness (e.g., < $50/kg). Here we report the development and preparation of Li 1.75 ZrCl 4.75 O 0.5 oxychloride solid-state electrolyte that demonstrates an ionic conductivity of 2.42 mS cm −1 at 25 °C, a compressibility enabling 94.2% density under 300 MPa and an estimated raw materials cost of $11.60/kg. As proof of concept, the Li 1.75 ZrCl 4.75 O 0.5 is tested in combination with a LiNi 0.8 Mn 0.1 Co 0.1 O 2 -based positive electrode and a Li 6 PS 5 Cl-coated Li-In negative electrode in lab-scale cell configuration. This all-solid-state cell delivers a discharge capacity retention of 70.34% (final discharge capacity of 70.2 mAh g −1 ) after 2082 cycles at 1 A g −1 , 25 °C and 1.5 tons of stacking pressure. Ionic conductivity > 1 mS cm −1 at 25 °C, compressibility enabling > 90% density at 250 − 350 MPa, and cost < $50/kg are desirable for inorganic solid-state electrolytes. Here, the authors report Li 1.75 ZrCl 4.75 O 0.5 as a solid-state electrolyte capable of satisfying these requirements simultaneously.

The use of lithium metal anodes in solid-state batteries has emerged as one of the most promising technologies for replacing conventional lithium-ion batteries 1 , 2 . Solid-state electrolytes are a key enabling technology for the safe operation of lithium metal batteries as they suppress the uncontrolled growth of lithium dendrites. However, the mechanical properties and electrochemical performance of current solid-state electrolytes do not meet the requirements for practical applications of lithium metal batteries. Here we report a class of elastomeric solid-state electrolytes with a three-dimensional interconnected plastic crystal phase. The elastomeric electrolytes show a combination of mechanical robustness, high ionic conductivity, low interfacial resistance and high lithium-ion transference number. The in situ-formed elastomer electrolyte on copper foils accommodates volume changes for prolonged lithium plating and stripping processes with a Coulombic efficiency of 100.0 per cent. Moreover, the elastomer electrolytes enable stable operation of the full cells under constrained conditions of a limited lithium source, a thin electrolyte and a high-loading LiNi 0.83 Mn 0.06 Co 0.11 O 2 cathode at a high voltage of 4.5 volts at ambient temperature, delivering a high specific energy exceeding 410 watt-hours per kilogram of electrode plus electrolyte. The elastomeric electrolyte system presents a powerful strategy for enabling stable operation of high-energy, solid-state lithium batteries. An elastomeric solid-state electrolyte shows desirable mechanical properties and high electrochemical stability, and is used to demonstrate a high-energy solid-state lithium battery at ambient temperature.

Solid polymer electrolytes (SPEs) and hydrogel electrolytes were developed as electrolytes for zinc ion batteries (ZIBs). Hydrogels can retain water molecules and provide high ionic conductivities; however, they contain many free water molecules, inevitably causing side reactions on the zinc anode. SPEs can enhance the stability of anodes, but they typically possess low ionic conductivities and result in high impedance. Here, we develop a lean water hydrogel electrolyte, aiming to balance ion transfer, anode stability, electrochemical stability window and resistance. This hydrogel is equipped with a molecular lubrication mechanism to ensure fast ion transportation. Additionally, this design leads to a widened electrochemical stability window and highly reversible zinc plating/ stripping. The full cell shows excellent cycling stability and capacity retentions at high and low current rates, respectively. Moreover, superior adhesion ability can be achieved, meeting the needs of flexible devices. Excess water in hydrogel-based zinc ion batteries causes side reactions, but reduced water content results in low conductivities. Here, authors develop a lean-water hydrogel based on molecular lubrication mechanism for fast ion transportation, extended stability, and reversible Zinc plating/stripping.

Dye-sensitized solar cells (DSCs) convert light into electricity by using photosensitizers adsorbed on the surface of nanocrystalline mesoporous titanium dioxide (TiO 2 ) films along with electrolytes or solid charge-transport materials 1 – 3 . They possess many features including transparency, multicolour and low-cost fabrication, and are being deployed in glass facades, skylights and greenhouses 4 . Recent development of sensitizers 5 – 10 , redox mediators 11 – 13 and device structures 14 has improved the performance of DSCs, particularly under ambient light conditions 14 – 17 . To further enhance their efficiency, it is pivotal to control the assembly of dye molecules on the surface of TiO 2 to favour charge generation. Here we report a route of pre-adsorbing a monolayer of a hydroxamic acid derivative on the surface of TiO 2 to improve the dye molecular packing and photovoltaic performance of two newly designed co-adsorbed sensitizers that harvest light quantitatively across the entire visible domain. The best performing cosensitized solar cells exhibited a power conversion efficiency of 15.2% (which has been independently confirmed) under a standard air mass of 1.5 global simulated sunlight, and showed long-term operational stability (500 h). Devices with a larger active area of 2.8 cm 2 exhibited a power conversion efficiency of 28.4% to 30.2% over a wide range of ambient light intensities, along with high stability. Our findings pave the way for facile access to high-performance DSCs and offer promising prospects for applications as power supplies and battery replacements for low-power electronic devices 18 – 20 that use ambient light as their energy source. Two newly designed co-adsorbed dye-sensitized solar cells that harvest light quantitatively across the entire visible domain are described, which offer promising applications as power supplies and battery replacements for low-power electronic devices.

Solid polymer electrolytes (SPEs), which are favorable to form intimate interfacial contacts with electrodes, are promising electrolyte of choice for long-cycling lithium metal batteries (LMBs). However, typical SPEs with easily oxidized oxygen-bearing polar groups exhibit narrow electrochemical stability window (ESW), making it impractical to increase specific capacity and energy density of SPE based LMBs with charging cut-off voltage of 4.5 V or higher. Here, we apply a polyfluorinated crosslinker to enhance oxidation resistance of SPEs. The crosslinked network facilitates transmission of the inductive electron-withdrawing effect of polyfluorinated segments. As a result, polyfluorinated crosslinked SPE exhibits a wide ESW, and the Li|SPE|LiNi 0.5 Co 0.2 Mn 0.3 O 2 cell with a cutoff voltage of 4.5 V delivers a high discharge specific capacity of ~164.19 mAh g −1 at 0.5 C and capacity retention of ~90% after 200 cycles. This work opens a direction in developing SPEs for long-cycling high-voltage LMBs by using polyfluorinated crosslinking strategy. Solid polymer electrolytes are commonly used in lithium-metal batteries, but their capacity and energy density cannot be easily increased beyond a charging cut-off voltage of 4.5 V due to the presence of easily oxidized oxygen-bearing polar groups. Here, authors apply a polyfluorinated crosslinker to enhance the oxidation resistance to solve this issue

Before the debut of lithium-ion batteries (LIBs) in the commodity market, solid-state lithium metal batteries (SSLMBs) were considered promising high-energy electrochemical energy storage systems before being almost abandoned in the late 1980s because of safety concerns. However, after three decades of development, LIB technologies are now approaching their energy content and safety limits imposed by the rocking chair chemistry. These aspects are prompting the revival of research activities in SSLMB technologies at both academic and industrial levels. In this perspective article, we present a personal reflection on solid polymer electrolytes (SPEs), spanning from early development to their implementation in SSLMBs, highlighting key milestones. In particular, we discuss the SPEs’ characteristics taking into account the concept of coupled and decoupled SPEs proposed by C. Austen Angell in the early 1990s. Possible remedies to improve the physicochemical and electrochemical properties of SPEs are also examined. With this article, we also aim to highlight the missing blocks in building ideal SSLMBs and stimulate research towards innovative electrolyte materials for future rechargeable high-energy batteries. Polymer electrolytes are attractive candidates for rechargeable lithium metal batteries. Here, the authors give a personal reflection on the structural design of coupled and decoupled polymer electrolytes and possible routes to further enhance their performance in rechargeable batteries.

Lithium bis(fluorosulfonyl)imide-based liquid electrolytes are promising for realizing high coulombic efficiency and long cycle life in next-generation Li-metal batteries. However, the role of anions in the formation of the solid–electrolyte interphase remains unclear. Here we combine electrochemical analyses and X-ray photoelectron spectroscopy measurements, both with and without sample washing, together with computational simulations, to propose the reaction pathways of electrolyte decomposition and correlate the interphase component solubility with the efficacy of passivation. We discover that not all the products derived from interphase-forming reactions are incorporated into the resulting passivation layer, with a notable portion present in the liquid electrolyte. We also find that the high-performance electrolytes can afford a sufficiently passivating interphase with minimized electrolyte decomposition, by incorporating more anion-decomposition products. Overall, this work presents a systematic approach of coupling electrochemical and surface analyses to paint a comprehensive picture of solid–electrolyte interphase formation, while identifying the key attributes of high-performance electrolytes to guide future designs. Li-metal batteries often utilize liquid electrolytes that yield a solid–electrolyte interphase on electrodes; however, the role of anions in interphase formation remains unclear. Now it has been shown that anion-decomposition products provide varying contributions to interphase formation and that high-performance electrolytes balance effective interfacial passivation with minimized degradation.