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High-stability and uniform Li deposition is essential for realizing applications of Li-metal batteries (LMBs). Therefore, a scaffold for polymer electrolytes is designed to achieve highly stable operation and dendrite-free Li...

Solid polymer electrolytes (SPEs) provide an intimate contact with electrodes and accommodate volume changes in the Li‐anode, making them ideal for all‐solid‐state batteries (ASSBs); however, confined chain swing, poor ion‐complex dissociation, and barricaded Li+‐transport pathways limit the ionic conductivity of SPEs. This study develops an interpenetrating polymer network electrolyte (IPNE) comprising poly(ethylene oxide)‐ and poly(vinylidene fluoride)‐based networked SPEs (O‐NSPE and F‐NSPE, respectively) and lithium bis(fluorosulfonyl) imide (LiFSI) to address these challenges. The CF2/CF3 segments of the F‐NSPE segregate FSI− to form connected Li+‐diffusion domains, and COC segments of the O‐NSPE dissociate the complexed ions to expedite Li+ transport. The synergy between O‐NSPE and F‐NSPE gives IPNE high ionic conductivity (≈1 mS cm−1) and a high Li‐transference number (≈0.7) at 30 °C. FSI− aggregation prevents the formation of a space‐charge zone on the Li‐anode surface to enable uniform Li deposition. In Li||Li cells, the proposed IPNE exhibits an exchange current density exceeding that of liquid electrolytes (LEs). A Li|IPNE|LiFePO4 ASSB achieves charge–discharge performance superior to that of LE‐based batteries and delivers a high rate of 7 mA cm−2. Exploiting the synergy between polymer networks to construct speedy Li+‐transport pathways is a promising approach to the further development of SPEs.

Interpenetrating Polymer Network Electrolyte In article number 2213469, Hsisheng Teng and co‐workers demonstrate a robust solid‐state lithium battery with synergy between O‐based and F‐based polymer networks, which overpowers liquid electrolyte batteries in terms of safety and performance. This synergistic relationship, combined with the creation of an anion‐aggregate domain, expedites Li+ transport in the battery.

Replacing organic liquid electrolytes with all-solid polymer electrolytes (SPEs) remedies various safety problems related to lithium ion batteries (LIBs). This work focuses on the design of SPE membranes with a backbone of poly(ethylene oxide) (PEO), containing no solvent, ionic liquid, oligomer, or semisolid additives, for LIBs operated at room temperature. Despite their ability in dissociating the lithium salt and Li+-ion coordination, PEO-based SPEs exhibit poor ionic conductivity at room temperature because their polymer chains tend to crystallize. Instead of adding inert fillers to suppress the crystallization tendency, this work employs functional linkers, such as silsesquioxanes, isocyanates, and triglycerides, to crosslink the PEO-based chains and produce a three-dimensional polymer network. These crosslinkers serve as hubs to facilitate effective Li+-ion motion. A low glass transition temperature and a low activation energy for ion conduction confirm the high segmental mobility of the polymer chains. When incorporated with a porous PVDF membrane, the SPEs exhibit high mechanical, chemical, and electrochemical stability, showing an ionic conductivity of ~ 10−4 S cm−1 and a stable potential of >5 V (vs. Li/Li+) at room temperature. The resulting Li|SPE|LiFePO4 batteries deliver discharge capacities of >155 and >135 mAh g−1 (based on LiFePO4) at 0.1 and 1 C-rates, respectively, at room temperature with an excellent charge-discharge cycling stability (>300 cycles).