Phase-Changeable Dynamic Conformal Electrode/electrolyte Interlayer enabling Pressure-Independent Solid-State Lithium Metal Batteries

Molten Guest-Mediated Metal-Organic Frameworks Featuring Multi-Modal Supramolecular Interaction Sites for Flame-Retardant Superionic Conductor in All-Solid-State Batteries

The development of solid-state electrolytes (SSEs) with outstanding comprehensive performance is currently a critical challenge for achieving high energy density and safer solid-state batteries (SSBs). In this study, a strategy of nano-confined in situ solidification is proposed to create a novel category of molten guest-mediated metal-organic frameworks, named MGM-MOFs. By embedding the newly developed molten crystalline organic electrolyte (ML20) into the nanocages of anionic MOF-OH, MGM-MOF-OH, characterized by multi-modal supramolecular interaction sites and continuous negative electrostatic environments within nano-channels, is achieved. These nanochannels promote ion transport through the successive hopping of Li+ between neighbored negative electrostatic environments and suppress anion movement through the chemical constraint of the hydroxyl-functionalized pore wall. This results in remarkable Li+ conductivity of 7.1 × 10-4 S cm-1 and high Li+ transference number of 0.81. Leveraging these advantages, the SSBs assembled with MGM-MOF-OH exhibit impressive cycle stability and a high specific energy density of 410.5 Wh kganode + cathode + electrolyte -1 under constrained conditions and various working temperatures. Unlike flammable traditional MOFs, MGM-MOF-OH demonstrates high robustness under various harsh conditions, including ignition, high voltage, and extended to humidity.

Decoration of Ag Species into Reduced Graphene Oxide Foam as a Superelastic and Robust Host toward Stable Zn Metal Anodes under Dwell-Fatigue Condition

Deep-sea equipment usually operates under dwell-fatigue condition, which means the equipped energy storage devices must survive under the changing pressure. Special mechanical designs should be considered to maintain the electrochemical performance of electrodes under this extreme condition. In this work, an effective assembly strategy is proposed to accommodate the dwell-fatigue loading using Ag decorated reduced graphene oxide (rGO) foam (denoted as AGF) as a superelastic and robust Zn host. The wet-press assembly process enables the formation of highly porous and robust framework. The strong synergetic effect between rGO and Ag further guarantees AGF's superelasticity and ultrahigh mechanical strength. Meanwhile, the homogeneously distributed Ag species on the rGO sheets act as zincophilic sites to effectively facilitate Zn plating. Furthermore, AGF offers enough space to address the expansion during the charge and discharge cycles. As expected, the symmetrical cell using this AGF@Zn host demonstrates a long lifespan over 400 h at a depth-of-discharge of 50%. It is worth mentioning that the superelastic AGF host realizes stable Zn plating/stripping under varying pressures.

A Lithium Intrusion-Blocking Interfacial Shield for Wide-Pressure-Range Solid-State Lithium Metal Batteries

Lithium garnets are considered as promising solid-state electrolytes for next-generation solid-state Li metal batteries (SSLBs). However, the Li intrusion driven by external stack pressure triggers premature of Li metal batteries. Herein, for the first time, an in situ constructed interfacial shield is reported to efficiently inhibit the pressure-induced Li intrusion in SSLBs. Theoretical modeling and experimental investigations reveal that high-hardness metallic Mo nanocrystals inside the shield effectively suppress Li dendrite growth without alloy hardening-derived interfacial contact deterioration. Meanwhile the electrically insulated Li2 S as a shield component considerably promotes interfacial wettability and hinders Li dendrite penetration into the bulk of garnet electrolyte. Interfacial shield-protected Li6.4 La3 Zr1.4 Ta0.6 O12 (LLZTO)-based cells exhibit significantly enhanced cyclability without short circuits under conventional pressures of ≈0.2 MPa and even at high pressure of up to 70 MPa; which is the highest endurable stack pressure reported for SSLBs using garnet electrolytes. These key findings are expected to promote the wide-pressure-range applications of SSLBs.

Tuning the Covalent Coupling Degree between the Cathode and Electrolyte for Optimized Interfacial Resistance in Solid-State Lithium Batteries

The development of promising solid-state lithium batteries has been a challenging task mainly due to the poor interfacial contact and high interfacial resistance at the electrode/solid-state electrolyte (SSE) interface. Herein, we propose a strategy for introducing a class of covalent interactions with varying covalent coupling degrees at the cathode/SSE interface. This method significantly reduces interfacial impedances by strengthening the interactions between the cathode and SSE. By adjusting the covalent coupling degree from low to high, an optimal interfacial impedance of 33 Ω cm^-2 was achieved, which is even lower than the interfacial impedance using liquid electrolytes (39 Ω cm^-2). This work offers a fresh perspective on solving the interfacial contact problem in solid-state lithium batteries.