Plastic Crystal Electrolytes Research Articles

Efficient sodium ion transport enhanced by anionophilic sites in polymer-supported plastic crystal electrolyte for high performance sodium metal anode

The design of sodium metal batteries (SMBs) is seen as an excellent solution to solve the request of next-generation energy storage technologies with high energy density, high safety, low cost, and environmental friendliness. However, the direct use of sodium metal as an anode produces the dendritic sodium, which harms the normal operation of battery. Inspired by solid-state lithium metal batteries, solid-state electrolyte (SSE) designed for SMBs effectively solves this shortcoming. Herein, a novel SSE with mask-based polymer membrane supporting plastic crystal electrolyte with ZIF-67 (MPPZ) is designed. The experimental results and density functional theory (DFT) calculations indicate that the addition of ZIF-67 in MPPZ electrolyte availably fixes TFSI− and achieves high Na+ transference number. Additionally, a protective layer of NaF is formed in situ on the surface of sodium metal to avoid side reactions between Na and MPPZ electrolyte while further guide the uniform deposition of Na. Accordingly, Na||Na symmetric battery with NaF-coated Na metal anode and MPPZ electrolyte has a stable deposition and stripping of Na for 3000 h. The assembled room temperature solid-state sodium-sulfur battery (RTSSSSB) exhibits a good cycle stability. This study provides an innovative thinking for the construction of high performance dendrite-free SMBs.

Plastic crystal as a plasticizer for enhancing Li+ ion conductivity in PMMA–LiTf polymer electrolyte

In this work, plastic crystal polymer electrolytes (PCPE) composed of polymethyl methacrylate (PMMA), lithium trifluoromethanesulfonate (LiTf), and succinonitrile (SN) were prepared using the solution casting method. The concentration of the plastic crystal SN was varied from 2 wt% to 20 wt%. The ionic conductivity of the PCPEs was measured at room temperature, with a maximum value of 5.75×10−5 S/cm observed for the PCPE with 10 wt% SN. An increase in the amorphous nature of the PCPE was noted from X-ray diffraction analysis, attributed to the interactions among PMMA, LiTf, and SN. FTIR analysis confirmed the presence of interactions among the components in the samples. A higher dielectric constant was obtained for the PCPE with 10 wt% SN. Dielectric tangent analysis revealed improved salt dissolution at higher concentrations of SN (20 wt%). The thermal stability of the PCPEs was also enhanced with the addition of SN.

Modulating the Li‐Ion Transport Pathway of Succinonitrile‐Based Plastic Crystalline Electrolytes for Solid‐State Lithium Metal Batteries

AbstractSuccinonitrile (SCN) based plastic crystal electrolytes (SPCEs) have attracted much attention for lithium metal batteries due to their considerable ionic conductivity and thermal stability. Insufficient mechanical properties, weak reductive stability, and the presence of free SCN molecules can result in adverse interfacial reactions. Polymer introduction has been explored to address these challenges. However, the introduction of polymer affects the SCN state, leading to reduced ionic conductivity, potentially due to limited segmental motion of the polymer at room temperature. Herein, a cross‐linked network polymer strategy is proposed to modify the Li‐ion transport pathway in SPCE, aiming to significantly improve the ionic conductivity. The strong interaction between the polymer matrix and SCN enhances their mutual solubility, reduces the crystallinity of SCN, and forms a rapid conduction pathway (polymer—[SCN—Li+]). The ionic conductivity of SPCE increases to 1.28 mS cm−1, with the Li‐ion migration number (tLi+ ) also rising to 0.7. Electrochemical performances in Li symmetrical, Li||LiFePO4 and Li||LiNi0.8Co0.1Mn0.1O2 cells show significant improvement at both room temperature and 0 °C. These findings suggest that designing polymer network structures in SPCEs holds promise for solid‐state lithium metal battery applications.

Solvent-free in-situ polymerized plastic crystal electrolytes for long-cycling lithium metal batteries

Solid polymer electrolytes (SPEs) are regarded as the pivotal materials for next-generation battery technology on account of their improved safety and potentially enabling higher energy density chemistry compared to conventional liquid electrolytes. However, the practical application of SPEs still hindered by the limited room temperature ionic conductivity, insufficient physical contact and unstable solid electrolyte interface (SEI) with electrodes. Here we report a class of in-situ polymerized plastic crystal electrolytes (PPCEs) which break the trade-offs between degree of polymerization and ionic conductivity of in-situ polymerized SPEs. The complete polymerized electrolytes combined both the advantages of in-situ polymer electrolytes and plastic crystal electrolytes, exhibiting thin thickness, good ionic conductivity, outstanding electrochemical stability and low interfacial impedance. As a result, symmetric Li cells with PPCE showed a superior long lifespan over 2500 h under 0.5 mA cm−2 and Li/PPCE/LiFePO4 (LiNi0.8Co0.1Mn0.1O2) cells displayed excellent long-cycling performance under 1.0 C at room temperature. The in-situ polymerized electrolyte system provides an effective strategy for developing safe and high-energy solid-state lithium batteries.

A Plastic-Crystal Electrolyte Layer Promotes Interfacial Stability of Ni-Rich Oxide Cathode in Li6PS5Cl-Based All-Solid-State Rechargeable Li Batteries.

Unfavorable parasitic reactions between the Ni-rich layered oxide cathode and the sulfide solid electrolyte have plagued the realization of all-solid-state rechargeable Li batteries. The accumulation of inactive by-products (P2Sx, S, POx n- and SOx n-) at the cathode-sulfide interface impedes fast Li-ion transfer, which accounts for sluggish reaction kinetics and significant loss of cathode capacity. Herein, we proposed an easily scalable approach to stabilize the cathode electrochemistry via coating the cathode particles by a uniform, Li+-conductive plastic-crystal electrolyte nanolayer on their surface. The electrolyte, which simply consists of succinonitrile and Li bis(trifluoromethanesulphonyl)imide, serves as an interfacial buffer to effectively suppress the adverse phase transition in highly delithiated cathode materials, and the loss of lattice oxygen and generation of inactive oxygenated by-products at the cathode-sulfide interface. Consequently, an all-solid-state rechargeable Li battery with the modified cathode delivers high specific capacities of 168 mAh g-1 at 0.1 C and a high capacity retention >80 % after 100 cycles. Our work sheds new light on rational design of electrode-electrolyte interface for the next-generation high-energy batteries.

Ternary stabilization strategies for succinonitrile-based in situ polymerized electrolyte enabling high-performance solid lithium metal batteries

Solid-state lithium metal batteries with high energy density and safety have gained increasing attention due to their potential applications. However, the practical use of solid electrolytes is hindered by several challenges. These include poor compatibility at the electrode–electrolyte interface, low ionic conductivity at room temperature, and fast capacity degradation. To address these issues, here we propose ternary strategies by in-situ cross-linked plastic crystal electrolyte (in-situ PCE) based on succinonitrile (SN). Through the in-situ polymerization of SN with polyacrylonitrile/poly(vinylidene difluoride) (PAN/PVDF) nanofibers separator, excellent mechanical strength and compatibility at the electrode–electrolyte interface are achieved. The cross-linked structure of thermally polymerized ethoxylated trimethylolpropane triacrylate (ETPTA) immobilizes the SN molecule, preventing its contact with the lithium metal and inhibiting irreversible side reactions. Additionally, a LiF-rich passivation layer is employed to further protect the SN at the electrolyte-lithium metal interface. The dual protection from ETPTA and LiF offers excellent stability to lithium. Hence, the in-situ PCE exhibits high ionic conductivity (0.79 mS cm−1 at 30 °C) and wide electrochemical window (4.56 V, vs Li+/Li). The cells exhibit excellent cycling stability and high-rate performance. LiFePO4//Li cells retain 96.6 % capacity after 1000 cycles at 10C rate. This study provides valuable insights into the development of high-performance solid-state electrolytes.

Heat capacities and role of defects in ion transfer of quinuclidinium hexafluorophosphate plastic crystal

To study the phase behavior and role of defects in the ion conduction of a well-investigated plastic crystal electrolyte, we measured the low-temperature heat capacities of quinuclidinium hexafluorophosphate ([HQ]PF6) plastic crystal and the defects of pure [HQ]PF6 and its mixtures containing lithium ions and chloride ions. The heat capacities of the pure material show two solid‒solid phase transitions at room temperature and a low temperature. Positron annihilation lifetime spectroscopy (PALS) revealed the phase dependence of the defect size for both the pure material and the mixtures. The defects in these two mixtures expand largely to approximately 2 (with Li+) and 2.5 (with Cl−) times larger than those in the pure material. The relationships between the ionic conductivity and vacancy volume of the pure material and the mixtures obey the Cohen−Turnbull free volume model, which is also phase dependent. This work help elucidate defect-assisted ion transfer in organic ionic plastic crystals.

Investigation of the benefits of the oxazolidinium cation for plastic crystal and ionic liquid electrolytes

Organic ionic plastic crystals (OIPCs) are promising for developing safer energy storage electrolytes. However, there remains a significant knowledge gap regarding how different cation-anion combinations influence their core properties, and cyclic ether-based cations have received limited attention. This study reports the synthesis and characterization of OIPCs based on the N-ethyl-N-methyl-oxazolidinium cation [C2moxa]+ and demonstrates the first instance of oxazolidinium OIPCs being combined with lithium salts to create electrolytes. The [C2moxa]+ cation was paired with [FSI]-, [TFSI]-, [BF4]-, [PF6]- and [FTFSI]- anions. A study of the thermal, transport and electrochemical properties was performed. Among the new salts developed, [C2moxa][BF4] exhibited the most promising characteristics, including the lowest entropy of melting (ΔS = 7 J mol−1 K−1), an extended phase I range (10°C–130°C), the highest conductivity of 8 x 10−6 S cm−1 at 30°C, and an electrochemical stability window of 4.8 V. When the [C2moxa][BF4] and [C2moxa][FSI] were mixed with lithium salts (10, 20 and 50 mol% Li+) of the same anion, the highest conductivity of 2 x 10−3 S cm−1 at 30°C was found for the 20 mol% LiFSI/[C2moxa][FSI] electrolyte. Finally, preliminary lithium plating/stripping experiments and coulombic efficiency (CE) measurements demonstrate stability for lithium cycling for all four [C2moxa]+ electrolytes.

Inducing an Amorphous Phase in Polymer Plastic Crystal Electrolyte for Effective Ion Transportation in Lithium Metal Batteries

AbstractPolymer plastic crystal electrolytes (PPCEs) have garnered significant attention for addressing the challenges associated with succinonitrile (SN), including its inadequate mechanical properties and side reactions with electrodes. However, a comprehensive investigation of the influence of the molecular structure of the polymer network on the states of SN within the network and its subsequent impact on ionic conductivities remains largely unexplored. To shed light on this critical aspect, the binding energy between SN and the polymer moiety is investigated as a determining factor in the conformation and crystallization behavior of SNs, through the dispersion‐corrected density functional theory (DFT‐D) simulations. These findings reveal that variations in miscibility resulting from the effects of binding energy significantly affected the formation of the amorphous phase in PPCEs. As a result, vinyl ethylene carbonate (VEC)‐based PPCE exhibits high ionic conductivity at room temperature (2.6 × 10−3 S cm−1 at 25 °C) and possesses a completely amorphous phase, which can be attributed to the optimized miscibility among its components. The feasibility of using a high‐performance solid‐state lithium‐metal battery (LMB) configuration is also examined by combining the PPCE with LiFePO4 (LFP) and LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode materials.

Stable Operation Induced by Plastic Crystal Electrolyte Used in Ni-Rich NMC811 Cathodes for Li-Ion Batteries.

The LiNi0.8Mn0.1Co0.1O2 (NMC811) cathode material has been of significant consideration owing to its high energy density for Li-ion batteries. However, the poor cycling stability in a carbonate electrolyte limits its further development. In this work, we report the excellent electrochemical performance of the NMC811 cathode using a rational electrolyte based on organic ionic plastic crystal N-ethyl-N-methyl pyrrolidinium bis(fluorosulfonyl)imide C2mpyr[FSI], with the addition of (1:1 mol) LiFSI salt. This plastic crystal electrolyte (PC) is a thick viscous liquid with an ionic conductivity of 2.3 × 10-3 S cm-1 and a high Li+ transference number of 0.4 at ambient temperature. The NMC811@PC cathode delivers a discharge capacity of 188 mA h g-1 at a rate of 0.2 C with a capacity retention of 94.5% after 200 cycles, much higher than that of using a carbonate electrolyte (54.3%). Moreover, the NMC811@PC cathode also exhibits a superior high-rate capability with a discharge capacity of 111.0 mA h g-1 at the 10 C rate. The significantly improved cycle performance of the NMC811@PC cathode can be attributed to the high Li+ conductivity of the PC electrolyte, the stable Li+ conductive CEI film, and the maintaining of particle integrity during long-term cycling. The admirable electrochemical performance of the NMC811|C2mpyr[FSI]:[LiFSI] system exhibits a promising application of the plastic crystal electrolyte for high voltage layered oxide cathode materials in advanced lithium-ion batteries.

Enabling long-term oxide based solid-state lithium metal battery through a near room-temperature sintering process

The huge Li ion transport resistance through the grain boundaries (GBs) among rigid oxide particles forces the adoption of high-temperature sintering (HTS) process over 1000 °C. Nevertheless, the severe side reactions and uncontrollable lithium loss are always companied during the high-cost HTS process, which slows down the pace of oxide solid electrolyte (OSE) for practical application and accelerates the exploration of a new OSE sintering process. Herein, a near-room-temperature (60 °C) cold-sintering process is proposed by filling the GBs with a low-melting-point plastic crystal electrolyte (PCE). Due to the soft property and high-ionic conductivity of PCE, the Li ion transport rate through the GBs is 10 times faster than the bulk phase, endowing the OSE (Li1.5Al0.5Ge1.5(PO4)3 chosen as a representative) with a room temperature ionic conductivity of 0.25 mS cm−1. As proof of the concept, the assembled Li symmetrical cells perform a low over-potential of 50 mV with a capacity of 1 mA h cm−2 and full cells delivers a capacity retention of roughly 70% after 820 cycles (1.5 years) at 0.1C.

Succinonitrile Plastic Crystal Polymer Electrolyte for Lithium Metal Battery

Polymer electrolyte has attracted wide attention due to the advantages of easy fabrication, lightweight, and good mechanical flexibility. However, polymer electrolyte exhibits limited ionic conductivity at room temperature, so the batteries can only be used above room temperature. Here, a succinonitrile plastic crystal polymer composite electrolyte (SCPE) with high content of succinonitrile (SN) was fabricated by in-situ polymerization. SCPE exhibits high ionic conductivity, which can be used at room temperature. In addition, SCPE exhibits excellent stability to lithium and can stable cycle over 1500 h without short circuits. Furthermore, LFP|SCPE|Li can achieve 150 stable cycles, presenting excellent cyclic stability performance. This research provides a feasible method for high room temperature ionic conductivity plastic crystal polymer electrolyte.

Investigation of the Physicochemical Properties of Pyrrolidinium-Based Mixed Plastic Crystal Electrolytes

Organic ionic plastic crystals (OIPCs) are promising candidates for solid-state electrolyte materials for energy storage applications. Mixing of two OIPCs to produce new solid-state electrolyte materials is proposed to be a route to increasing defects/disorder in the materials, which may in turn promote ion transport. In this work, the thermal phase behavior and transport properties of two different pyrrolidinium-based binary OIPC mixtures were investigated. The most promising was the mixture of N,N-diethylpyrrolidinium bis(fluorosulfonyl)imide ([C2epyr][FSI]) and N-isopropyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide ([C(i3)mpyr][FSI]), studied across the entire composition range, where the 10 mol % [C(i3)mpyr][FSI] mixture showed the highest ionic conductivity of 2 × 10–5 S cm–1 at 30 °C, consistent with the increased ion dynamics indicated by solid-state NMR analysis. Synchrotron XRD analysis revealed that the addition of 10 mol % [C(i3)mpyr][FSI] to [C2epyr][FSI] contributed to lattice expansion, hinting at increased defect volume and/or rotational disorder that assists with improved transport properties. Additionally, 10 mol % LiFSI was added to the chosen binary OIPC mixtures to investigate their potential use as electrolytes. The 10 mol % binary mixture with 10 mol % LiFSI showed the highest ionic conductivity (1.8 × 10–3 S cm–1 at 30 °C), while PFG analysis showed that the [FSI]− anions in the 10 mol % mixture with Li-salt have the highest diffusivity compared to other binary mixtures with Li-salt. Analysis of the structure-dynamics of mixed pyrrolidinium-based binary OIPCs provides insights into this scarcely explored strategy for improving the physicochemical properties of plastic crystal systems and toward the development of improved solid-state electrolytes for battery applications.

In Situ Thermal Polymerization of a Succinonitrile-Based Gel Polymer Electrolyte for Lithium-Oxygen Batteries.

For lithium-oxygen batteries (LOBs), the leakage and volatilization of a liquid electrolyte and its poor electrochemical performance are the main reasons for the slow industrial advancement. Searching for more stable electrolyte substrates and reducing the use of liquid solvents are crucial to the development of LOBs. In this work, a well-designed succinonitrile-based (SN) gel polymer electrolyte (GPE-SLFE) is prepared by in situ thermal cross-linking of an ethoxylate trimethylolpropane triacrylate (ETPTA) monomer. The continuous Li+ transfer channel, formed by the synergistic effect of an SN-based plastic crystal electrolyte and an ETPTA polymer network, endows the GPE-SLFE with a high room-temperature ionic conductivity (1.61 mS cm-1 at 25 °C), a high lithium-ion transference number (tLi+ = 0.489), and excellent long-term stability of the Li/GPE-SLFE/Li symmetric cell at a current density of 0.1 mA cm-2 for over 220 h. Furthermore, cells with the GPE-SLFE exhibit a high discharge specific capacity of 4629.7 mAh g-1 and achieve 40 cycles.

High‐Performance Dual‐Salt Plastic Crystal Electrolyte Enabled by Succinonitrile‐Regulated Porous Polymer Host

AbstractSuccinonitrile (SN)‐based plastic crystal electrolytes (PCE) show great promise for solid‐state lithium‐metal batteries (LMBs) because of their outstanding electrochemical properties. However, limited by the low mechanical strength of SN, SN‐based PCEs are difficult to act as an independent self‐supporting electrolyte films, which seriously restricts their practical application. In this study, a SN‐regulated poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) porous host is proposed via a facile phase separation method as a promising strategy for addressing this issue, which enables a high‐performance dual‐salt SN‐based PCE (named as DPCE). The as‐prepared host simultaneously provides homogeneous porous network and robust mechanical support, which is convenient to accommodate DPCE evenly and increases the strength of DPCE to restrict dendrites growth. As a result, with this efficient host, the Li symmetric cell assembled with DPCE shows superior long‐term stability for >1200 h at a current density of 0.1 mA cm−2. Moreover, the assembled Li|LiFePO4 cell delivers a high‐capacity retention of 99.3% after 700 cycles under 2 C at room temperature, demonstrating the promising potential for developing high‐performance solid‐state LMBs.

Long-cycling High-voltage lithium metal batteries enabled by Anion-concentrated plastic crystal electrolytes

Solid-state electrolytes (SSEs) have been attached widespread attention as next-generation materials as far as safety and energy density are concerned, but they are severely plagued by the limited oxidative potential, and poor physical contact with electrodes. In the present work, we developed anion-concentrated plastic crystal electrolyte (APCE) with normal lithium salt concentration but high concentration of anion based on ionic plastic crystals (IPCs) contain the same anion lithium salt. This strategy ensures the good stability of as-developed electrolytes and make use of some advantages of concentrated electrolytes such as excellent electrochemical window and superior long-cycling stability with metal anode. Also, the deformable property of IPC ensures good physical contact of APCE with electrodes. As a result, solid-state symmetric Li cells, high-voltage Li/LiNi0.6Co0.2Mn0.2O2 and ∼5.0 V class Li/LiNi1.5Mn0.5O4 coin cells with APCE exhibit superior long-cycling performance at 25 °C. Furthermore, the ionic nature of IPC guarantees the safety of APCE so that it can past the harsh penetration test under practical conditions and the APCE-based pouch cell shows excellent flexibility, acceptable rate performance and a high energy density of 253.1Wh kg−1. It is anticipated that our works provide a strategy for next-generation solid-state batteries.

“Polymer-in-ceramic” PEO/2D heterojunction composite electrolytes for solid-state batteries

The ferroelectric spontaneous polarizability of the piezoelectric TBA+CNO− also has an enhanced effect on ion transport and electrode interface modification, and its ferroelectric spontaneous polarization field also helps to reduce the generation and growth of anode dendrites. The structural instability of LRAP electrolyte Li2.99Ba0.005OCl are maintained by forming a heterojunction structure with two-dimensional nanosheets TBA+CNO−, and the fast conduction channels of lithium ions (Li+) are established. Composite electrolytes possess Li+ conductivity σi > 10−4 S/cm at 25°C. The composite materials composed of “polymer-in-ceramic” with flexibility and mechanical strength are fabricated by the casting method. PEO-Li2.99Ba0.005OCl/TBA+CNO− shows good compatibility with lithium metal, forming a stable solid electrolyte interface. The plastic crystal electrolyte dripped on the cathode side avoids the direct contact between high-voltage cathode and electrolyte and protects PEO from being oxidized and decomposed. NCM811|Li batteries show 70.9 mAh•g−1 with capacity retention of 97.88% after 100 cycles.

Laminar composite solid electrolyte with succinonitrile-penetrating metal-organic framework (MOF) for stable anode interface in solid-state lithium metal battery

Succinonitrile (SN) plastic crystal electrolyte holds great promise for high-performance solid-state lithium metal batteries due to its high ionic conduction. However, the serious side reaction between SN and lithium anode always causes large interfacial resistance, deteriorating the battery capacity. Herein, we penetrated LiTFSI-SN (LSN) electrolyte into the interlayer channels of laminar metal-organic framework (MOF), then an ultra-thin and stable laminar LiTFSI–SN–MOF composite solid-state electrolyte (LSN-MOF CSE) was obtained. We demonstrate that the interlayer nanochannels for LSN electrolyte storage without sacrificing the mobility of SN molecules. Meanwhile, the unsaturated coordination of MOF, induced by Co/Ni metal sites, causes a horizontal arrangement of SN. Therefore, this electrolyte offers a remarkable ionic conductivity of 7.41 × 10−4 S cm−1 at 25 °C. Moreover, the interlayer nanochannels and covalent interaction of MOF synergistically suppress the migration of SN to lithium anode, thus improving the interface stability of lithium anode. Importantly, the assembled Li symmetrical cell performs stable operation over 800 h under 0.2 mA cm−2, and the LiFePO4/Li cell delivers excellent cycling stability of 148.2 mAh g−1 with a low capacity decay of 0.048% per cycle after 200 cycles under 0.2C and 25 °C.

A solid-state lithium-oxygen battery operating at ambient temperature and full charge-discharge

Solid-state Li-O2 batteries (SSLOBs) have been denoted as the holy grail in next-generation Li metal batteries for their high theoretical energy density, manipulation of ambient air to energy storage as well as high safety. However, the solid rigid interfaces both at the cathode and anode side introduce ultra-high resistances in the battery system and impede its operation under ambient temperature. Moreover, the high-reductive Li anode and semi-open cathode would cause severe side reactions during cycling which further degrade battery performance. To manage the above-mentioned issues, a rationally designed SSLOBs based on plastic crystal electrolyte is proposed in this study to enable SSLOBs operation at ambient temperature and in full charge-discharge mode. The brand-new Li-O2 battery has been improved mainly from two aspects. First, we propose a polyacrylonitrile (PAN) modified succinonitrile (SN) electrolyte (PAN-SN) to retard the polymerization of SN and meanwhile suppress the degradation of Li ionic conductivity. Second, we propose an alternative mixed electron/ion complex conductor (MEIC) cathode to coordinate with plastic crystal electrolyte with an expanded Li-O2 reactive zone and improved interfacial charge transfer during the charge-discharge process. The fabricated flexible SSLOBs based on PAN-SN electrolyte and MEIC cathode could be successfully fully charged-discharged (cutoff 2.0–4.5 V) for tens of cycles at ambient temperature under simulated air condition (20 vol% oxygen), with high-capacity retention of around 85 %.

Double-layer Composite Gel Polymer Electrolyte for Organic Sodium-Metal Batteries.

Organic cathode materials have the advantages of abundant raw materials, high theoretical specific capacity, controllable structure and easy recycling. Pyrene-4,5,9,10-tetraone (PTO), as one of the typical organic cathode materials, achieves efficient storage and release of Na+ . However, its good solubility in traditional organic liquid electrolytes is detrimental to the cyclic stability of batteries. To address this issue, the double-layer composite gel polymer electrolyte (DLCGPE) consisting of poly (ionic liquid) gel polymer electrolyte and plastic crystal electrolyte was developed and applied to organic sodium-metal batteries. This as-prepared DLCGPE displays an ionic conductivity of 2.17×10-4 S cm-1 and an electrochemical window of 4.8 V. The as-fabricated sodium-symmetric batteries maintain interfacial stability after 500 h of cycling. Furthermore, the PTO/Na batteries could also retain a specific capacity of 201 mAh g-1 after 300 cycles, confirming that DLCGPE achieves the purpose of inhibiting PTO dissolution and maintaining batteries stability. This work broadens the application of asymmetric electrolytes in organic secondary battery.