Qinmin Pan

Polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP)-based solid-state electrolytes have emerged as promising candidates for lithium metal batteries (LMBs) because of their electrochemical stability and mechanical robustness. However, their practical application in LMBs is constrained by intrinsically low ionic conductivity and instability of electrode/electrolyte interfaces, especially at wide-temperature range. This study introduces a wide-temperature flexible polyurethane (PU) into PVDF-HFP to fabricate a solid polymer electrolyte (SPE) with fast Li⁺ transportation kinetics at wide-temperature range. The flexible PU framework endows the SPE with exceptional thermal stability up to 120℃ and compact contact to electrodes at -10℃, as well as high ionic conductivity at RT (4.71×10^-4 S/cm) and -10℃ (9.31×10^-5 S/cm). Solid-state Li||LiFePO₄ batteries using the SPE achieve a capacity retention of 85.4% after 1000 cycles at 0.5 C. Remarkably, the batteries exhibit operational capability across a wide temperature range, maintaining 81.4% capacity retention after 500 cycles at 90℃ (1 C) and stable cyclability at 0℃ with a specific capacity of 100 mAh/g. This study proposes a kind of high-performance solid polymer electrolyte for solid-state LMBs operated under extreme-temperature conditions.

Solid polymer electrolytes (SPEs) have attracted significant attention in next‐generation solid‐state batteries (SSBs). However, SPEs‐based SSBs suffer from performance fading and safety concerns at high temperatures caused by the thermal instability and degradation of their electrode/electrolyte interfaces. Herein, a poly(vinylene carbonate‐co‐methyl acrylate)‐based solid polymer electrolyte (PVC‐MA‐SPE) with a highly self‐adaptive structure is designed. The resulting PVC‐MA‐SPE exhibits an ionic conductivity of 4.93 × 10 ⁻⁴ S cm ⁻¹ at 120 °C and high adhesion to electrodes. At zero pressure, solid‐state Li|PVC‐MA‐SPE|LFP batteries maintain 152.6 mAh g ⁻¹ discharge capacity and 95.4% capacity retention after 150 cycles at 1C and 120 °C. The mechanism for the improved performance is attributed to the strong intermolecular interaction of the poly(vinylene carbonate‐co‐methyl acrylate) (PVC‐MA) network with volatile molecules. Importantly, the PVC‐MA network not only enables the SPE to tightly contact with electrodes, but also contributes to forming thermally stable SEI/CEI enriched in flexible polymeric components and LiF. These properties result in enhanced interfacial stability at high temperature. This work presents a novel approach to enhance the intrinsic safety of solid‐state batteries at high temperatures.

The construction of interfacial bridges in PAN-based PISE via the in situ polymerization of DOL simultaneously solves the ion-conduction problems both in the bulk and at the electrolyte/electrode interface in a PISE-based SSLSB.

Solid‐state polymer lithium metal batteries (SSLMBs) have attracted considerable attention because of their excellent safety and high energy density. However, the application of SSLMBs is significantly impeded by uneven Li deposition at the interface between solid‐state electrolytes and lithium metal anode, especially at a low temperature. Herein, this issue is addressed by designing an agarose‐based solid polymer electrolyte containing branched structure. The star‐structured polymer is synthesized by grafting poly (ethylene glycol) monomethyl‐ether methacrylate and lithium 2‐acrylamido‐2‐methylpropanesulfonate onto tannic acid. The star structure regulates Li‐ion flux in the bulk of the electrolyte and at the electrolyte/electrode interfaces. This unique omnidirectional Li‐ion transportation effectively improves ionic conductivity, facilitates a uniform Li‐ion flux, inhibits Li dendrite growth, and alleviates polarization. As a result, a solid‐state LiFePO ₄ ||Li battery with the electrolyte exhibits outstanding cyclability with a specific capacity of 134 mAh g ⁻¹ at 0.5C after 800 cycles. The battery shows a high discharge capacity of 145 mAh g ⁻¹ at 0.1 C after 200 cycles, even at 0 °C. The study offers a promising strategy to address the uneven Li deposition at the solid‐state electrolyte/electrode interface, which has potential applications in long‐life solid‐state lithium metal batteries at a low temperature.

We report a composite polymer electrolyte with PEG brushes that act as “ion sieves” and “Li⁺ bridges”, thus enabling fast Li⁺ transport in the interior of the electrolyte as well as at the electrolyte/electrode interfaces.

Solid polymer electrolytes (SPEs) are promising for solid-state lithium batteries, but their practical application is significantly impeded by their low ionic conductivity and poor compatibility. Here, we report an ultrahigh elastic SPE based on cross-linked polyurethane (PU), succinonitrile (SN), and lithium bistrifluoromethanesulfonimide (LiTFSI). The resulting electrolyte (PU-SN-LiTFSI) exhibits an ionic conductivity of 2.86 × 10^–4 S cm^–1, a tensile strength of 3.8 MPa, and a breaking elongation exceeding 3000% at room temperature. A solid-state lithium battery using the electrolyte exhibits a high specific capacity of 150 mAh g^–1 at 0.2C and a long cycling life of up to 700 cycles at 0.5C at room temperature, showing one of the best performances among its counterparts. The excellent performances are attributed to the fact that its ultrahigh elasticity, good ionic conductivity, tensile strength, and electrochemical stability contribute to robust electrode/electrolyte interfaces, thus greatly decreasing the charge-transfer resistance in charge/discharge processes. Our investigations provide a novel strategy to address the intrinsic interfacial issue of solid-state batteries.

Solid-state lithium batteries are considered as a promising candidate for next-generation energy storage systems because of their high safety and energy density. The solid polymer electrolyte is a paramount component in solid-state lithium batteries. However, it is still a challenge to realize an ultra-thin electrolyte with both high ionic conductivity and mechanical strength. Herein, an ultra-thin polymer electrolyte (UTPE) is prepared by grafting agarose with polyethylene oxide (PEO) in the presence of isophorone diisocyanate (IPDI). The as-prepared electrolyte shows an ionic conductivity of 1.2 × 10⁻⁴ S cm⁻¹ at room temperature, a tensile strength of up to 5.5 MPa and a thickness lower than 32 μm. A Li symmetric cell using the UTPE can stably cycle for 600 h at room temperature. A solid-state LiFePO₄‖Li battery with the UTPE delivers a specific capacity of 131 mA h g⁻¹ over 600 cycles at a 1.0C rate at room temperature, showing a retention rate of 92.9%. Furthermore, a pouch solid-state battery shows good reliability and safety even after being folded, cut and penetrated by a nail. The present investigation offers a novel pathway to design ultra-thin electrolytes aiming for solid-state lithium batteries with high energy density and reliability.

Lithium (Li) metal is a promising anode for high-energy-density batteries, but its practical applications are severely hindered by side reactions and dendrite growth at the electrode/electrolyte interfaces. Herein, we propose that the problems can be effectively solved by introducing an interlayer. The interlayer is composed of a trifluorophenyl-modified poly(ethylene imine) network cross-linked by dynamic imine bonding (PEI-3F). The trifluorophenyl moieties of the interlayer can coordinate with Li⁺, which enables the interlayer to adjust the distribution of Li⁺ at the electrode/electrolyte interface, while the imine bonding endows the interlayer with self-healing capability. The resulting Li anodes exhibit excellent cycling stability (250 cycles in asymmetric Li||Cu cells) and dendrite-free morphologies. A lithium sulfur (Li-S) cell that uses anodes shows a retention rate of 91% after 100 cycles with a high sulfur loading (5 mg cm^–2). This study provides a novel strategy to concern the intrinsic drawbacks of a lithium metal anode, which can be extended to other light-metal electrodes aiming for high energy-density batteries.