High‐Performance Quasi‐Solid‐State Pouch Cells Enabled by in situ Solidification of a Novel Polymer Electrolyte

Abstract

Conventional lithium‐ion batteries (LIBs) with liquid electrolytes are challenged by their big safety concerns, particularly used in electric vehicles. All‐solid‐state batteries using solid‐state electrolytes have been proposed to significantly improve safety yet are impeded by poor interfacial solid–solid contact and fast interface degradation. As a compromising strategy, in situ solidification has been proposed in recent years to fabricate quasi‐solid‐state batteries, which have great advantages in constructing intimate interfaces and cost‐effective mass manufacturing. In this work, quasi‐solid‐state pouch cells with high loading electrodes (≥3 mAh cm−2) were fabricated via in situ solidification of poly(ethylene glycol)diacrylate‐based polymer electrolytes (PEGDA‐PEs). Both single‐layer and multilayer quasi‐solid‐state pouch cells (2.0 Ah) have demonstrated stable electrochemical performance over 500 cycles. The superb electrochemical stability is closely related to the formation of robust and compatible interphase, which successfully inhibits interfacial side reactions and prevents interfacial structural degradation. This work demonstrates that in situ solidification is a facile and cost‐effective approach to fabricate quasi‐solid‐state pouch cells with both excellent electrochemical performance and safety.

In Situ Polymerization Inhibiting Electron Localization in Hybrid Electrolyte for Room‐Temperature Solid‐State Lithium Metal Batteries

“…The excellent interfacial contact between the electrode and the electrolyte is crucial for achieving safer rechargeable lithium batteries. [30,31] The interfacial contact between PDL-10 SSE poured onto 2D and 3D Li anodes was evaluated and compared (Figure 4e-g). By comparing the impedance boxplots, 3D Li//PDL-10 SSE exhibit lower (≈150 Ω) and more stably distributed impedance than 2D Li//PDL-10 SSE, indicating that the 3D Li//PDL-10 SSE had better contact with the 3D Li anode than the 2D Li anode at room temperature.…”

Fiber-reinforced quasi-solid polymer electrolytes enabling stable Li-metal batteries

“…(3) The Li electrode in an organic liquid electrolyte also leads to serious safety issues, such as electrolyte leakage, gas formation and even explosion. [17][18][19][20] Solid electrolytes, including inorganic solid electrolytes and solid polymer electrolytes, have been considered as more promising candidates to inhibit the Li dendrite growth and address the safety issues of LMBs. [21][22][23][24][25] Generally, an ideal solid electrolyte should possess high ionic conductivity, good mechanical strength, and an intimate electrode/electrolyte interface.…”

“…(3) The Li electrode in an organic liquid electrolyte also leads to serious safety issues, such as electrolyte leakage, gas formation and even explosion. 17–20…”

In Situ Formed Poly(ester-alt-acetal) Electrolytes with High Oxidation Potential and Electrode–Electrolyte Interface Stability

“…24 During the in situ polymerization process for LMBs, the surface of the electrodes can be fully wetted first by the monomers, leading to the filling of gaps and defects, and the performance of such PE-based batteries can be significantly enhanced in comparison to traditional PEs. 25,26 Due to the high reactivity of metallic lithium, lithium metal reacts continuously with the PEs (and possibly unreacted monomers) on the anode side, resulting in the consumption of active materials, a decrease in battery capacity, and even safety accidents. 27−30 On the cathode side, the difficult-to-improve electrolyte oxidation resistance is still the bottleneck of highvoltage and high-energy-storage LMBs.…”

“…Given the escalating need for safe energy storage devices with high energy density, nonvolatile polymer electrolytes (PEs) for lithium metal batteries (LMBs) have emerged as a focal point of current research. , The development of PEs with improved ionic conductivity, thermal stability, electrode–electrolyte interface stability, and compatibility is overwhelming and on the road. − Thereof, the preparation of PEs by in situ polymerization is an emerging method for the preparation of LMBs with enhanced interfacial compatibility and battery performance. , The typical PEs produced by in situ polymerization have been widely investigated, such as poly­(dioxolane) from cationic polymerization of dioxolane, − poly­(vinylene carbonate) from free radical polymerization of vinyl carbonate, , and poly­(ethylene glycol) diglycidyl ether from anionic polymerization of ethylene oxide . During the in situ polymerization process for LMBs, the surface of the electrodes can be fully wetted first by the monomers, leading to the filling of gaps and defects, and the performance of such PE-based batteries can be significantly enhanced in comparison to traditional PEs. , …”