An Organic/Inorganic Composite Gel Electrolyte Inducing Uniformly Lithium Deposition at High Current Density and Capacity

Abstract

Although gel polymer electrolytes (GPEs) have attracted tremendous attention for lithium metal batteries due to their high ionic conductivity, high safety, and excellent adaptability, it is still challenging to suppress the uncontrollable lithium dendrite growth for GPEs. Here, an organic/inorganic composite gel electrolyte (PPPL) as GPEs is proposed, which is formed by ring‐opening polymerization reaction of poly(methyl vinyl ether‐alt‐maleic anhydride) (PMVE‐MA) and polyethylene glycol (PEG) in polymer matrix of poly(vinylidene fluoride‐hexafluoropropylene) (PVDF‐HFP) embedded with Li6.4La3Zr1.4Ta0.6O12 (LLZTO) particles. The PMVE‐MA participates in the formation of a stable solid electrolyte interface (SEI) and the PEG greatly improves the flexibility of PPPL. The PPPL exhibits excellent performance in terms of a wide electrochemical window (4.7 V), high lithium transference number (0.59), and satisfactory mechanical strength (11 MPa). Besides, the PPPL contributes to the formation of stable and flexible SEI containing organic components and LiF on lithium metal, and constructs fast and uniform lithium transport channels to effectively suppress the lithium dendrite growth. The Li/PPPL/Li symmetric batteries can stably cycle 800 h at the high current density of 5 mA cm–2 and capacity of 5 mAh cm–2. The outstanding electrochemical performance of the PPPL will provide important insights for design of advanced GPEs.

Diversifying Ion-Transport Pathways of Composite Solid Electrolytes for High-Performance Solid-State Lithium-Metal Batteries

“…The surficial chemical environment between ceramics and polymers is crucial for the ionic conductivity of CSEs, the stability of ceramic/polymer interface, and the electrochemical performance of SSLMBs. − In the polymer-based CSEs, the overall ionic conductivity increases upon adding ceramics into polymer matrixes due to the compromised crystallinity and extra Li-ion-transport pathways provided by ceramics . With increased content of ceramics (>20 wt %), a decrease in Li-ion conductivity is observed, which could be attributed to agglomeration of ceramic particles, leading to the discontinuous Li-ion transport in ceramics. , Particle agglomeration also results in the nonuniform distribution of a large amount of crystallized polymers, as well as restricted Li-ion transport at the interface between polymers and ceramics (Figure a). , Therefore, engineering the ceramic/polymer interface is necessitated to elevate the electrochemical performance of CSEs. , …”

“…11,19 Therefore, engineering the ceramic/polymer interface is necessitated to elevate the electrochemical performance of CSEs. 20,21 Various polymer coatings have been applied based on Lewis acid−base interactions to improve the contact area between ceramics and polymers and increase the concentration of free Li ions at the interface, such as polyethylene carbonate (PEC), 22 polydopamine (PDA), 23−29 poly-1,3-dioxolane (PDOL), 30 and poly(methyl methacrylate) (PMMA). 31 Among them, PDA has been widely studied owing to its excellent binding properties and simple modification methods.…”

Perspectives on Li Dendrite Penetration in Li7La3Zr2O12‐Based Solid‐State Electrolytes and Batteries: Materials, Interfaces, and Charge Transfer

“…[1] Lithium (Li) metal anode material is promising to significantly improve the energy density of batteries, as it possesses ultrahigh theoretical capacity (3860 mAh g −1 ) and the lowest electrochemical potential (−3.04 V vs standard hydrogen DOI: 10.1002/aenm.202303128 electrode (SHE)). [2] A new generation of stable electrolytes that is compatible with Li metal has attracted extensive attention since it plays a key role in the electrochemical reaction and battery performance. [3] The commercially employed liquid organic electrolytes in LIBs are not suitable for the highly reactive Li metal anode or the high voltage cathode due to their narrow electrochemical window.…”

Porous Metal Current Collectors for Alkali Metal Batteries

“…[19][20][21][22] Although the theoretical specific capacity and electrochemical potential of alkali metal are beneficial for achieving high energy density, these alkali metal anodes still face the problem of uneven alkali metal deposition which probably results in dendrite growth, low Coulombic efficiency, and thereby the short lifetime of batteries. [23][24][25][26][27] Recently, considerable efforts have been devoted to preventing the growth of dendrites and prolonging the stability of alkali metal anodes, including the strategies of interface regulation, [28,29] anode structure engineering, [30] electrolyte optimization, [30,31,32] stress release, [33] and self-healing mechanism utilization. [34] It is generally accepted that the dendrite growth is caused by the uneven current and ion distribution on the anode surface.…”