Gel Electrolyte Research Articles

An in-situ polymerization strategy for gel polymer electrolyte Si||Ni-rich lithium-ion batteries

Coupling the Si-based anodes with nickel-rich LiNixMnyCo1−x−yO2 cathodes (x ≥ 0.8) in the energy-dense cell prototype suffers from the mechanical instability of the Li-Si alloys, cathode collapse upon the high-voltage cycling, as well as the severe leakage current at elevated temperatures. More seriously, the cathode-to-anode cross-talk effect of transitional metal aggravates the depletion of the active Li reservoir. To reconcile the cation utilization degree, stress dissipation, and extreme temperature tolerance of the Si-based anode||NMC prototype, we propose a gel polymer electrolyte to reinforce the mechanical integrity of Si anode and chelate with the transitional cations towards the stabilized interfacial property. As coupling the conformal gel polymer electrolyte encapsulation with the spatial arranged Si anode and NMC811 cathode, the 2.7 Ah pouch-format cell could achieve the high energy density of 325.9 Wh kg−1 (based on the whole pouch cell), 88.7% capacity retention for 2000 cycles, self-extinguish property as well as a wide temperature tolerance. Therefore, this proposed polymerization strategy provides a leap toward the secured Li batteries.

Interfacial fusion-enhanced 11 µm-thick gel polymer electrolyte for high-performance lithium metal batteries

In the pursuit of ultrathin polymer electrolyte (<20 μm) for lithium metal batteries, achieving a balance between mechanical strength and interfacial stability is crucial for the longevity of the electrolytes. Herein, 11 μm-thick gel polymer electrolyte is designed via an integrated electrode/electrolyte structure supported by lithium metal anode. Benefiting from an exemplary superiority of excellent mechanical property, high ionic conductivity, and robust interfacial adhesion, the in-situ formed polymer electrolyte reinforced by titanosiloxane networks (ISPTS) embodies multifunctional roles of physical barrier, ionic carrier, and artificial protective layer at the interface. The potent interfacial interactions foster a seamless fusion of the electrode/electrolyte interfaces and enable continuous ion transport. Moreover, the built-in ISPTS electrolyte participates in the formation of gradient solid-electrolyte interphase (SEI) layer, which enhances the SEI’s structural integrity against the strain induced by volume fluctuations of lithium anode. Consequently, the resultant 11 μm-thick ISPTS electrolyte enables lithium symmetric cells with cycling stability over 600 h and LiFePO4 cells with remarkable capacity retention of 96.6% after 800 cycles. This study provides a new avenue for designing ultrathin polymer electrolytes towards stable, safe, and high-energy–density lithium metal batteries.

Internally connected porous PVA/PAA membrane with cross-aligned nanofiber network for facile and long-lasting ion transport in zinc–air batteries

In response to the growing interest in next-generation wearable devices, the demand for high-performance, safe, and flexible power sources has increased. Flexible zinc–air batteries (ZABs) based on gel polymer electrolytes (GPEs) have emerged as promising candidates for wearable power sources owing to their high energy density, safety, and cost efficiency. However, persistent electrolyte evaporation through the air cathode poses a significant challenge, resulting in poor lifespan characteristics that impede practical applications. In this study, we developed a polymer composite-type GPE composed of cross-aligned nanofibers (NFs) of a polyacrylic acid (PAA)-based framework embedded in a polyvinyl alcohol (PVA) matrix. Upon immersion in a liquid electrolyte (6 M KOH), the superabsorbent PAA spontaneously generated an internally connected porous (IP) structure adjacent to the aligned PAA NFs. These pores served as directional water channels, facilitating rapid hydroxide ion conduction and yielding a remarkable ionic conductivity of 235.7 mS cm−1. The PVA matrix acts as both a packaging material and the main body of the GPE, providing good dimensional stability and mitigating the swelling of PAA, even under conditions of high electrolyte uptake, while also ensuring high flexibility. The IP-PVA/PAA composite GPE demonstrated a high power output, rate performance, and excellent lifespan in flexible ZABs. Furthermore, successful operation at various bending angles provides empirical evidence supporting the viable application of flexible ZABs.

Effect of Fluorine Segments in Fluoropolymer matrix on the Properties of Gel Polymer Electrolytes

Polymer quasi‐solid electrolytes have been paid widely attention in account of their outstanding advantages in safety, flexibility, viscoelasticity and film formation. Fluoropolymer is used as matrix of gel electrolytes not only has high electrochemical stability, but also facilitates the dissociation of lithium salts owning to the strong electron‐absorbing C‐F groups, which makes it a very promising choice for the further development of gel electrolytes. Due to the different sites of C‐F bonds, their activity is also diverse, which results in the difference of the mobility of lithium ions and the LiF composition of SEI film on the surface of lithium metal anode. As a result, distinct fluorine‐containing gel polymer electrolytes are prepared by in‐situ polymerization of two different monomers, HFMA and TFMA. Compared with ‐CF3 on terminal group in TFMA, the gel electrolyte polymerized with HFMA whose C‐F group with stronger electronegativity is at the intermediate carbon site, as polymer matrix has better performance. The ionic conductivity achieves 7.02×10−3 S cm−1 at room temperature, and the assembled batteries have a capacity retention rate of 91% after 200 cycles of 1 C. Our research has laid a solid theoretical foundation for the further development of quasi‐solid electrolyte.

MnO2 Nanoparticles Decorated PEDOT:PSS for High Performance Stretchable and Transparent Supercapacitors.

With the swift advancement of wearable electronics and artificial intelligence, the integration of electronic devices with the human body has advanced significantly, leading to enhanced real-time health monitoring and remote disease diagnosis. Despite progress in developing stretchable materials with skin-like mechanical properties, there remains a need for materials that also exhibit high optical transparency. Supercapacitors, as promising energy storage devices, offer advantages such as portability, long cycle life, and rapid charge/discharge rates, but achieving high capacity, stretchability, and transparency simultaneously remains challenging. This study combines the stretchable, transparent polymer PEDOT:PSS with MnO2 nanoparticles to develop high-performance, stretchable, and transparent supercapacitors. PEDOT:PSS films were deposited on a PDMS substrate using a spin-coating method, followed by electrochemical deposition of MnO2 nanoparticles. This method ensured that the nanosized MnO2 particles were uniformly distributed, maintaining the transparency and stretchability of PEDOT:PSS. The resulting PEDOT:PSS/MnO2 nanoparticle electrodes were gathered into a symmetric device using a LiCl/PVA gel electrolyte, achieving an areal capacitance of 1.14 mF cm-2 at 71.2% transparency and maintaining 89.92% capacitance after 5000 cycles of 20% strain. This work presents a scalable and economical technique to manufacturing supercapacitors that combine high capacity, transparency, and mechanical stretchability, suggesting potential applications in wearable electronics.

Ultraviolet-cured heat-resistant and stretchable gel polymer electrolytes for flexible and safe semi-solid lithium-ion batteries

Lithium-ion (Li-ion) batteries assembled with gel polymer electrolytes (GPEs) are predicted to increase battery energy density while maintaining battery safety. In this work, poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) is successfully used as a polymer matrix to prepare a new kind of GPE (PHHNT) by ultraviolet (UV) curing technology. The polymer network structure formed by photopolymerization technology significantly enhances the tensile properties of the electrolyte. Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) improves the concentration and transport efficiency of lithium ions in the electrolyte as well as the ionic conductivity (1.22 × 10−3 S cm−1) of the GPEs. In addition, the unique tubular structure of the halloysite nanotube (HNT) and the opposite charges carried by the inner and outer surfaces provide additional channels for the lithium salt and facilitate its dissociation. This enhances the expedited movement of Li+ inside the electrolyte, while simultaneously improving the electrochemical and thermal durability of the electrolyte. The assembled LiFePO4 (LFP)/PHHNT/Li battery has an initial discharge-specific capacity of 140.5 mAhg−1 at a current density of 0.5C, showing a high capacity retention rate of 89 % after 120 cycles. The design of this composite material significantly improves the overall performance of the electrolyte and is more suitable for flexible and safe solid-state Li-ion batteries.

High-voltage (> 3 V) energy storage device based on sputter-grown TiCrN microelectrodes towards miniaturized applications

In this work, we report sputter-grown micro-patterns of titanium chromium-based bimetallic nitride (TiCrN) over Si/SiO2 substrate. The highly stable TiCrN-micro pattern is tested electrochemically and used to construct an efficient microsupercapacitor (MSC) device. To achieve a stable and high-voltage window, a non-aqueous gel polymer electrolyte (GPE) of TEABF4/EC/PC/PVDF is optimized. At room temperature, the GPE exhibits high ionic conductivity of ~10.58 mS cm−1 with exceptional mechanical stability. A symmetric supercapacitor based on TiCrN sandwich structure (TiCrN-SS) is fabricated with TEABF4 GPE for practical application. The TiCrN-SS device works on a high voltage of 3.1 V and exhibits good electrochemical properties. The device shows a high energy density of 1.9 μWh cm−2 (5.9 Wh kg−1) at a power density of 109 μW cm−2 (0.34 kW kg−1). To utilize the excellent performance of TiCrN-SS as a miniaturized power source, an on-chip MSC is subsequently fabricated by patterning planar interdigitated TiCrN-microelectrodes. The constructed on-chip TiCrN microsupercapacitor (TiCrN-MSC) works on a wide voltage window of 0–3.1 V while maintaining an optimum areal capacitance of ~500 μF cm−2 at 0.07 mA cm−2 current density. The device exhibits an areal energy density of ~0.7 μWh cm−2 with an optimum 169.02 μW cm−2 power density. This remarkable electrochemical performance and exceptionally wide voltage window of TiCrN-based MSC makes it a potential candidate for direct use as a miniaturized power source in microelectronic devices.

Entropy-Driven Hybrid Gel Electrolyte Enables Practical High-Voltage Lithium Metal Batteries.

Electrolyte engineering plays a crucial role in enhancing the performance of lithium metal batteries (LMBs) featuring high-voltage cathodes and limited lithium anodes, thereby unlocking their potential for high-energy electrochemical storage. Herein, an entropy-driven hybrid gel electrolyte with enhanced diversity in Li-ion solvation structures is designed by incorporating substantial amounts of insoluble LiPO2F2 and LiNO3 salts into LiPF6-based carbonate electrolytes, followed by in situ thermal polymerization. Specifically, the Li+ solvation structures are modulated via ionophilic NO3- and PO2F2- to generate an anion-rich solvation sheath and thus promote anion reduction at the electrode-electrolyte interface. The interfaces enriched in anion-derived inorganic components facilitate rapid ionic transport, thus enabling smooth and dense Li morphology and ultimately enhancing the electrochemical performance of LMBs. As a result, this high-hybrid gel electrolyte confers LMBs employing high-voltage NCM cathodes, as demonstrated by sustained performance in both coin-cell (500 cycles at 4.5 V) and Ah-level pouch cell configurations under practical conditions (60 cycles, N/P: 1.92, and E/C: 2.0 g Ah -1).

Enhanced Zinc–Air Batteries through the Fabrication of Structured Zinc Electrodes Using Freeze‐Casting

Ice‐templating, a versatile manufacturing process, is widely utilized to create porous materials by freezing aqueous solutions. Notably, this technique is material independent, allowing for the fabrication of microstructured bulk or sheet materials of ceramic, glass, metal, polymer, and composite materials. Herein, the influence of freeze‐cast zinc electrodes on zinc–air batteries is investigated. The analysis includes the charge and discharge cycling behavior of pure powder, gel matrix, and sintered freeze‐cast zinc electrodes, complemented by the study of the distribution of relaxation times. Remarkably, the best cycling performance is achieved with the combination of a gel electrolyte and a freeze‐cast zinc electrode, highlighting the potential significance of this microstructure–electrolyte pairing for enhancing the performance of zinc–air batteries.

Safety enhanced novel polymer electrolytes for lithium-ion battery: Anomalous output performance with long term cycling stability by doping and polymer blending

Electrolyte with better safety and stability are the primary concern in the present lithium-ion battery (LIB) technology. Herein, a unique polymer blend electrolyte of polyvinylidene difluoride (PVdF)/poly (acrylonitrile butadiene styrene) (ABS) (75: 25) is fabricated by the non-solvent induced phase inversion method. The structural, morphological, and electrochemical performance of the PVdF/ABS blend is enhanced by incorporating the silica nanoparticles as the ceramic filler by the in-situ method. The gel polymer electrolyte (GPE) constitutes 6 wt % of in-situ synthesised silica in PVdF/ABS blend (PASI-06) exhibits better microporous structure with 80 % porosity. The thermal shrinkage, thermogravimetric analysis (TGA) and flammability test safeguards the exceptional thermal stability of the polymer membrane in LIBs. The polymer membrane activated in the liquid electrolyte (1 M LiPF6 in EC:EMC:DMC (1: 1: 1 v/v)) reveals an electrolyte uptake of 400 %, high electrolyte retention (0.82) and a room temperature ionic conductivity of 5.7 mS cm−1. The better oxidative stability exhibited by the PASI-06 (4.5 V) ensures its applicability with high voltage cathodes. Moreover, the electrochemical performance of the coin cell constitutes of Li/GPE/LFP able to exhibits an initial discharge capacity of 143 mAh g−1 and retained a capacity of 115 mAh g−1 even after 200 cycles at 0.1 C-rate at 25 °C. The long term cycling stability evaluated over 500 cycles at 1 C shows that the cell can exhibit an initial discharge capacity 120 mAh g−1 with 77 % capacity retention over 500 cycles that corresponds to 99 % of coulombic efficiency. These excellent performances exhibited by the PASI-06 GPE guarantee its applicability in thermally stable LIBs with better safety and reliability.

Rational design and elucidation of interfacial dynamics in PMMA/PVDF compatibilized blends through solution blending for stable quasi-solid-state dye-sensitized solar cells

In the photovoltaic market, the widespread adoption of traditional dye-sensitized solar cells (DSSCs) faces obstacles due to inherent stability challenges. The solution to these issues involves replacing liquid electrolytes with quasi-solid electrolytes. In this work, quasi-solid state electrolytes were synthesized by employing a polymer blend and inorganic salt. The polymeric blends, comprising polymethyl methacrylate (PMMA) and polyvinylidene fluoride (PVDF), were meticulously prepared through the solution blending technique. The investigation of blend compatibility, crystallinity, and stability involved analyses through differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-degradation assessments, respectively. The findings indicated that the concentration of ingredients significantly influenced the compatibility, crystallinity, and stability of the blends. The compatibilized blend was employed in crafting polymer gel electrolytes (PEGs), demonstrating that both the concentration and type of salts significantly influence the ionic conductivity of PEGs. The highest conductivity, reaching 2 mS/cm, was achieved with a mixed salt concentration of 50w%/50w% (NH4I/KI). Subsequently, this electrolyte was incorporated into the fabrication of quasi-solid state DSSC. The results showed that the DSSC with PEG achieved 2.81 % efficiency, while the traditional DSSC had 4.11 % efficiency. Notably, after fifteen days, the efficiency of the traditional DSSC dropped to 0.20 %, while the PEG-based DSSC remained stable (2.58 %).

In situ synthesis of cross-linking gel polymer electrolyte for lithium metal batteries

The room temperature ionic conductivity of polyethylene oxide (PEO)-based polymer electrolytes is low, the electrochemical window is narrow, and the mechanical strength is relatively poor. In this work, a cross-linking gel-based solid composite polymer electrolyte (CG-SCPE) was synthesized by introducing electrochemically stable carbonate-based functional groups. The synthesized CG-SCPE presents excellent tensile strength (26 MPa) and a wide electrochemical stability window (> 4.5 V vs. Li/Li+). Meanwhile, the in situ polymerization method induced by thermal heating resulted in good compatibility between electrodes/electrolytes. In addition, the assembled LiNi0.5Co0.2Mn0.3O2/CG-SCPE/Li battery exhibited satisfactory electrochemical performance. Therefore, the gel polymer electrolyte CG-SCPE with cross-linking network provides the possibility for future application of safe and high-performance solid-state lithium metal batteries. The results indicate that the introduction of cross-linking framework can simultaneously improve the mechanical strength, thermal stability, and electrochemical performance of solid polymer electrolyte.

Preparation and Evaluation of PVDF-HFP-Based Gel Electrolyte for Ge-Sensitized Thermal Cell.

The semiconductor-sensitized thermal cell (STC) is a new thermoelectric conversion technology. The development of nonliquid electrolytes is the top priority for the practical application of the STC. In this study, a novel gel polymer electrolyte (PH-based GPE) composed of poly(vinylidenefluoride-co-hexafluoropropylene) (PH), 1-Methyl-2-pyrrolidone (NMP), and Cu ions was synthesized and applied to the STC system. The PH-based GPE synthesized at 45 °C showed higher open-circuit voltage (-0.3 V), short-circuit current density (59 μA cm-2) and diffusion coefficient (7.82 × 10-12 m2 s-1), indicating that a well-balanced structure among the NMP molecules was formed to generate a high-efficiency conduction path of the Cu ions. Moreover, the ion diffusion lengths decreased with decreasing content rates of NMP for the PH-based GPEs, indicating that the NMP plays an important role in the diffusion of Cu ions. Furthermore, the activation energy was calculated to be 107 kJ mol-1, and that was smaller compared to 150 kJ mol-1 for the poly(ethylene glycol)-based liquid electrolyte. These results play an important reference role in the development of electrolytes for STC systems. At the same time, they also provide a new avenue and reference indicator for the synthesis of high-performance and safe GPEs.

Perovskite-structured ceramic zinc titanate nanomaterials: A comparative study of photovoltaic and synthetic approaches

Ternary metal oxide materials are being explored as potential electrode materials for dye-sensitized solar cells due to their adjustable electronic band structures through elemental composition modifications. Perovskite materials based on zinc and titanium have been utilised in DSSC and show moderate performance. Considerable research has been dedicated to this field to improve their performances. The focus was primarily on the synthetic variabilities due to their impact on performance under varying synthetic conditions. According to this perspective, no comparative studies have found superior methodologies for utilising zinc titanate as a potential photoanode in DSSC. We synthesised a zinc titanate material using thermal, sol-gel, and plasma irradiation techniques. The materials' structural variability was analysed using PXRD and FT-IR techniques. A mixed-phase composition of spinel cubic and hexagonal has been identified. The SEM images provide insights into the particle distribution and morphology of the zinc titanate materials. Investigating absorption properties, band gap energy levels and aggregation behaviours provided initial insights into the potential use of the three zinc titanate materials. The DSSC devices were fabricated using zinc titanate materials with varying properties, and the results are detailed in this discussion. Based on the findings, the plasma and thermal irradiation techniques yielded more favourable zinc titanate materials for dye-sensitized solar cell use. The efficiency reached 0.04 % when operating with polymeric gel electrolytes.

In Situ Polymerization Bi-Functional Gel Polymer Electrolyte for High Performance Quasi-Solid-State Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries are expected to be the next-generation energy storage system due to the ultrahigh theoretical energy density and low cost. However, the notorious shuttle effect of higher-order polysulfides and the uncontrollable lithium dendrite growth are the two biggest challenges for commercially viable Li-S batteries. Herein, these two main challenges are solved by in situ polymerization of bi-functional gel polymer electrolyte (GPE). The initiator (SiCl4) not only drives the polymerization of 1,3-dioxolane (DOL) but also induces the construction of a hybrid solid electrolyte interphase (SEI) with inorganic-rich compositions on the Li anode. In addition, diatomaceous earth (DE) is added and anchored in the GPE to obtain PDOL-SiCl4-DE electrolyte through in situ polymerization. Combined with density functional theory (DFT) calculations, the hybrid SEI provides abundant adsorption sites for the deposition of Li+, inhibiting the growth of lithium dendrites. Meanwhile, the shuttle effect is greatly alleviated due to the strong adsorption capacity of DE toward lithium polysulfides. Therefore, the Li/Li symmetric cell and Li-S full cell assembled with PDOL-SiCl4-DE exhibit excellent cycling stability. This study offers a valuable reference for the development of high performance and safe Li-S batteries.

Resilient 3D porous self-healable triple network hydrogels reinforced with graphene oxide for high-performance flexible supercapacitors

The application of gel polymer electrolyte (GPE) in flexible supercapacitor (FSC) has attracted much attention due to its excellent mechanical properties and chemical stability. However, traditional polymer substrates have high crystallinity, resulting in sluggish ion migration and low ionic conductivity. This study reports the successful fabrication of a resilient highly porous triple hydrogel network (TNH) comprising the natural polymer of sodium alginate and biocompatible components of polyvinyl alcohol and graphene oxide (GO), exhibiting remarkably high ionic conductivity and astonishing mechanical strength, self-healing, and flame retardant properties. The physical and electrochemical features of the GPEs were optimized by tuning the GO wt% within the polymeric matrix. Adding a low wt% of GO (0.8 wt%) led to remarkable improvements in ionic conductivity (83.33 mS cm−1), mechanical strength (2.21 MPa), and self-healing and flame-retardant properties of the resulting PVA/SA/GO GPE than the pristine GPE. This was attributed to the formation of a microporous three-dimensional polymeric network based on reversible non-covalent bonds. The carbon cloth-based symmetric SC prepared based on this GPE exhibited a long cycle life, high specific capacitance of 633.3 mF cm−2 at 0.5 mA cm−2, and an energy density of 84 mWh cm−2 at a high power density of 500.2 mW cm−2 (at 1 mA cm−2)), which surpassed the values reported in previous studies. The electrochemical performance of the FSC prepared based on PVA/SA/GO GPE remained constant when subjected to bending deformation, indicating the harmonious physical, chemical, and electrochemical properties of the developed GPE and its suitability for flexible energy storage devices, and wearable electronics

High toughness antifreeze conductive double network zwitterionic gel electrolyte for flexible supercapacitors

AbstractFlexible wearable supercapacitors based on hydrogel electrolyte are considered as flexible energy storage device with great potential. However, polymer gel electrolytes contain a large number of water molecules, which can easily freeze at sub‐zero temperatures, thus severely inhibiting ion transport. The ionic conductivity, cyclic stability and mechanical properties of gel electrolytes decrease at low temperatures (below −25°C), which seriously hinders the application of flexible wearable supercapacitors. In order to improve the mechanical properties and ensure the excellent ionic conductivity of the electrolyte, a freezing‐resistant gel electrolyte constructed by supramolecular self‐assembly, which has a wide temperature range from 25 to −80°C, stable ionic conductivity and ultra‐high mechanical strength. Low‐temperature‐resistant gel electrolytes, called flexible supercapacitor‐SBMA‐co‐PVA‐AA/CaCl2 (FSAPC), have been designed and prepared by molecular‐scale supramolecular self‐assembly of rigid [2‐(methacryloyloxy)ethyl]dimethyl(3‐sulfopropyl) polymer chains and flexible poly(vinyl alcohol) polymer chains, and the test results showed that the gel electrolyte ‐SBMA‐co‐PVA‐AA/CaCl2 (PSAPC) has excellent conductivity of 34.07 mS cm−1 at 25°C, the flexible supercapacitor has a specific capacity of 8.57 Wh kg−1, and the capacity retention rate is 91.2% even after 5000 cycles at −25°C, excellent conductivity at −25°C for 31.88 mS cm−1 and at −80°C for 35.34 mS cm−1. The potential applications of the amphiphilic ionic gel electrolyte in the industrial development of low‐temperature resistant supercapacitors are noteworthy.

Breaking Solvation Dominance of Phosphate via Dipole–Dipole Chemistry in Gel Polymer Electrolyte

Breaking Solvation Dominance of Phosphate via Dipole–Dipole Chemistry in Gel Polymer Electrolyte

An Ionic Liquid Supramolecular Gel Electrolyte with Unique Wide Operating Temperature Range Properties for Zinc-Ion Batteries.

Zinc-ion batteries are promising candidates for large-scale energy storage. The side reactions of the hydrogen evolution reaction (HER) and zinc dendrite growth are major challenges for developing high-performance zinc-ion batteries. In this paper, a supramolecular gel electrolyte (BLO-ILZE) was self-assembled in an ionic liquid (EMIMBF4) with zinc tetrafluoroborate (Zn(BF4)2) on the separator in situ to obtain a gel electrolyte used in zinc-ion batteries. BLO-ILZE is demonstrated to significantly enhance conductivity over a broad temperature range between -70 and 100 °C. Interestingly, through testing and fitting, it is found that the supramolecular gel electrolyte satisfies the liquid state law over a wide temperature range, and even achieves high conductivity (2.12 mS cm-1) at -40 °C. It is equivalent to the conductivity of aqueous zinc-ion batteries (ZnSO4/H2O) at -10 °C, which is 2.33 mS cm-1. Moreover, the supramolecular gel electrolyte can effectively inhibit the HER, thus exhibiting a longer lifetime in Zn/Zn cells for 3470 h at 1 mA cm-2 compared to the aqueous zinc-ion batteries with the Zn(BF4)2 aqueous electrolyte (400 h at 1 mA cm-2). The assembled V2O5/BLO-ILZE/Zn full cells also showed cycling performance, with 5000 cycles at 0.5 mA g-1 at room temperature, a capacity of 98%, and a coulombic efficiency of about 100%.

Friendly Environmental Strategies to Recycle Zinc-Carbon Batteries for Excellent Gel Polymer Electrolyte (PVA-ZnSO4-H2SO4) and Carbon Materials for Symmetrical Solid-State Supercapacitors.

In this report, we introduce a novel idea to prepare a redox additive in a gel polymer electrolyte system of PVA-ZnSO4-H2SO4 based on zinc-carbon battery recycling. Here, zinc cans from spent zinc-carbon batteries are dissolved completely in 1 M H2SO4 to obtain a redox additive in an aqueous electrolyte of ZnSO4-H2SO4. Moreover, carbon nanoparticles and graphene nanosheets were synthesized from carbon rod and carbon powder from spent zinc-carbon batteries by only one step of washing and electrochemical exfoliation, respectively, which have good electrochemical capability. The three-electrode system using a ZnSO4-H2SO4 electrolyte with carbon nanoparticles and graphene nanosheets as working electrodes shows high electrochemical adaptability, which points out its promising application in supercapacitor devices. Thus, the symmetrical solid-state supercapacitor devices based on the sandwich structure of graphene nanosheets/PVA-ZnSO4-H2SO4/graphene nanosheets illustrated the highest energy density of 39.17 W h kg-1 at a power density of 1700 W kg-1. While symmetrical devices based on carbon nanoparticles/PVA-ZnSO4-H2SO4/carbon nanoparticles exhibited a maximum energy density of 35.65 W h kg-1 at a power density of 1700 W kg-1. Moreover, these devices illustrate strong durability after 5000 cycles, with approximately 90.2% and 73.1% remaining, respectively. These results provide a promising strategy for almost completely recycling zinc-carbon batteries, one of the most popular dry batteries.