Electrochemically-Matched and Nonflammable Janus Solid Electrolyte for Lithium-Metal Batteries

Integrated Janus gel with bilayered heterostructure for high-performance supercapacitors

A persistent challenge for electrolytes is achieving simultaneous compatibility with both electrodes under high-voltage conditions, which has restricted the power output of energy storage devices. Herein, we developed an integrated Janus gel electrolyte with a bilayer heterostructure to extend the potential limits on both the cathode and anode. This electrolyte consisted of a deep eutectic solvent (DES) gel phase and an ionic liquid (IL) gel phase. The DES gel layer functioned as the anolyte, benefiting from its reduction tolerance through internal H-bond interactions, while the IL gel phase served as the catholyte, taking advantage of the high oxidation resistance of TFSI-. Moreover, the miscibility between DES and IL enabled full integration of the intermediate layer, effectively reducing interfacial transmission impedance and promoting ions migration. The fabricated Janus gel demonstrated a wide electrochemical window (4.70 V), satisfactory ionic conductivity (3.57 mS/cm), and excellent temperature tolerance. A supercapacitor incorporating this Janus gel electrolyte delivered an energy density of 89.4 Wh/kg at the power density of 646.2 W/kg under the voltage window of 3.6 V (-1.8∼1.8 V), along with robust cycling stability over 10,000 charge-discharge cycles. An energy density of 31.4 Wh/kg at a power density of 386.5 W/kg could be maintained in the voltage range of 0∼1.8 V. This research provides novel insights into the design of engineered electrolytes that are high compatible with both the cathode and anode in high-voltage applications.

Review of the Developments and Difficulties in Inorganic Solid-State Electrolytes

All-solid-state lithium-ion batteries (ASSLIBs), with their exceptional attributes, have captured the attention of researchers. They offer a viable solution to the inherent flaws of traditional lithium-ion batteries. The crux of an ASSLB lies in its solid-state electrolyte (SSE) which shows higher stability and safety compared to liquid electrolyte. Additionally, it holds the promise of being compatible with Li metal anode, thereby realizing higher capacity. Inorganic SSEs have undergone tremendous developments in the last few decades; however, their practical applications still face difficulties such as the electrode-electrolyte interface, air stability, and so on. The structural composition of inorganic electrolytes is inherently linked to the advantages and difficulties they present. This article provides a comprehensive explanation of the development, structure, and Li-ion transport mechanism of representative inorganic SSEs. Moreover, corresponding difficulties such as interface issues and air stability as well as possible solutions are also discussed.

Task-Specific Janus Materials in Heterogeneous Catalysis

Janus materials are anisotropic nano- and microarchitectures with two different faces consisting of distinguishable or opposite physicochemical properties. In parallel with the discovery of new methods for the fabrication of these materials, decisive progress has been made in their application, for example, in biological science, catalysis, pharmaceuticals, and, more recently, in battery technology. This Minireview systematically covers recent and significant achievements in the application of task-specific Janus nanomaterials as heterogeneous catalysts in various types of chemical reactions, including reduction, oxidative desulfurization and dye degradation, asymmetric catalysis, biomass transformation, cascade reactions, oxidation, transition-metal-catalyzed cross-coupling reactions, electro- and photocatalytic reactions, as well as gas-phase reactions. Finally, an outlook on possible future applications is given.

Optimized Interfaces in Anti-Perovskite Electrolyte-Based Solid-State Lithium Metal Batteries for Enhanced Performance

Solid-state lithium metal batteries have attracted broad interest as a promising energy storage technology because of the high energy density and enhanced safety that are highly desired in the markets of consumer electronics and electric vehicles. However, there are still many challenges before the practical application of the new battery. One of the major challenges is the poor interface between lithium metal electrodes and solid electrolytes, which eventually lead to the exceptionally high internal resistance of the cells and limited output. The interface issue arises largely due to the poor contact between solid and solid, and the mechanical/electrochemical instability of the interface. In this work, an in situ “welding” strategy is developed to address the interfacial issue in solid-state batteries. Microliter-level of liquid electrolyte is transformed into an organic–inorganic composite buffer layer, offering a flexible and stable interface and promoting enhanced electrochemical performance. Symmetric lithium–metal batteries with the new interface demonstrate good cycling performance for 400 h and withstand the current density of 0.4 mA cm⁻². Full batteries developed with lithium–metal anode and LiFePO₄ cathode also demonstrate significantly improved cycling endurance and capacity retention.