Excellent Interfacial Compatibility Research Articles

Polyoxometalate Li3PW12O40 and Li3PMo12O40 Electrolytes for High‐energy All‐solid‐state Lithium Batteries

AbstractSolid‐state lithium (Li) batteries promise both high energy density and safety while existing solid‐state electrolytes (SSEs) fail to satisfy the rigorous requirements of battery operations. Herein, novel polyoxometalate SSEs, Li3PW12O40 and Li3PMo12O40, are synthesized, which exhibit excellent interfacial compatibility with electrodes and chemical stability, overcoming the limitations of conventional SSEs. A high ionic conductivity of 0.89 mS cm−1 and a low activation energy of 0.23 eV are obtained due to the optimized three‐dimensional Li+ migration network of Li3PW12O40. Li3PW12O40 exhibits a wide window of electrochemical stability that can both accommodate the Li anode and high‐voltage cathodes. As a result, all‐solid‐state Li metal batteries fabricated with Li/Li3PW12O40/LiNi0.5Co0.2Mn0.3O2 display a stable cycling up to 100 cycles with a cutoff voltage of 4.35 V and an areal capacity of more than 4 mAh cm−2, as well as a cost‐competitive SSEs price of $5.68 kg−1. Moreover, Li3PMo12O40 homologous to Li3PW12O40 was obtained via isomorphous substitution, which formed a low‐resistance interface with Li3PW12O40. Applications of Li3PW12O40 and Li3PMo12O40 in Li‐air batteries further demonstrate that long cycle life (650 cycles) can be achieved. This strategy provides a facile, low‐cost strategy to construct efficient and scalable solid polyoxometalate electrolytes for high‐energy solid‐state Li metal batteries.

Polyoxometalate Li3 PW12 O40 and Li3 PMo12 O40 Electrolytes for High-energy All-solid-state Lithium Batteries.

Solid-state lithium (Li) batteries promise both high energy density and safety while existing solid-state electrolytes (SSEs) fail to satisfy the rigorous requirements of battery operations. Herein, novel polyoxometalate SSEs, Li3 PW12 O40 and Li3 PMo12 O40 , are synthesized, which exhibit excellent interfacial compatibility with electrodes and chemical stability, overcoming the limitations of conventional SSEs. A high ionic conductivity of 0.89 mS cm-1 and a low activation energy of 0.23 eV are obtained due to the optimized three-dimensional Li+ migration network of Li3 PW12 O40 . Li3 PW12 O40 exhibits a wide window of electrochemical stability that can both accommodate the Li anode and high-voltage cathodes. As a result, all-solid-state Li metal batteries fabricated with Li/Li3 PW12 O40 /LiNi0.5 Co0.2 Mn0.3 O2 display a stable cycling up to 100 cycles with a cutoff voltage of 4.35 V and an areal capacity of more than 4 mAh cm-2 , as well as a cost-competitive SSEs price of $5.68 kg-1 . Moreover, Li3 PMo12 O40 homologous to Li3 PW12 O40 was obtained via isomorphous substitution, which formed a low-resistance interface with Li3 PW12 O40 . Applications of Li3 PW12 O40 and Li3 PMo12 O40 in Li-air batteries further demonstrate that long cycle life (650 cycles) can be achieved. This strategy provides a facile, low-cost strategy to construct efficient and scalable solid polyoxometalate electrolytes for high-energy solid-state Li metal batteries.

Green, recyclable, mechanically robust, wet-adhesive and ionically conductive cellulose-based bioplastics enabled by supramolecular covalent hydrophobic eutectic networks

The development of novel cellulose-based bioplastics (CBPs) is highly desirable because CBPs are green, rationally use resources, and lead to a reduction in environmental pollution compared to alternative materials. However, incorporating high transparency, water resistance, mechanical robustness, wet-adhesion, ionic conductivity and recyclability into CBP remains a challenge. In this paper, novel CBPs with supramolecular covalent networks are fabricated by introducing polymerizable hydrophobic deep eutectic solvents (HDES) into ethylcellulose (EC) networks through in situ plasticization followed by a rapid photopolymerization process. The excellent molecular interfacial compatibility enables EC to be loaded with a high content of poly(HDES), while allowing high transparency (more than 90 %) of the prepared CBPs. Multiple intermolecular interactions provide CBPs with mechanical robustness, water resistance, and underwater adhesion, and CBPs can be readily recovered by the solvent in a closed loop. Moreover, CBPs possess inherent ionic conductivities, and using them as green substrates, personalized electroluminescent devices can be successfully constructed. The method proposed in this paper provides a new strategy for the preparation of multifunctional CBPs, which will greatly enrich their applications in self-adhesive materials, green flexible electronics and other package materials.

Hierarchical bulk-interface design of MOFs framework for polymer electrolyte towards ultra-stable quasi-solid-state Li metal batteries

The sluggish ion transportation, oxidation instability and severe lithium dendrites impede the development of solid-state lithium metal battery (SSLMBs). Herein, a novel structural design of in-situ polymerized composite electrolyte (CPE) with the utilization of both orientationally arranged and unilaterally sedimented Zeolitic imidazolate framework-67 (ZIF-67) fillers are reported. The in-situ growing of ZIF-67 crystals on 3D polyvinylidene fluoride (PVDF) nanofiber skeleton not only provides high-speed Li+ conduction pathway, but also promotes the antioxidative ability of surrounding polymer matrix by facilitating the ring-open polymerization of 1,3-Dioxolane (DOL) monomer to form long-chain PDOL. Meanwhile, ZIF-67 deposition layer constructed through the natural sedimentation of residual ZIF-67 during PVDF@ZIF-67 framework fabrication regulates surface Li+ flux towards lithium anode and further optimizes SEI composition. As a result, satisfactory ionic conductivity of 1.8 × 10−4 S cm−1 and oxidative potential of 5.9 V (vs. Li+/Li) are acquired for unilateral-sedimented ZIF-67/PDOL CPE (UZE). Encouragingly, symmetric Li battery based on UZE displays a superior stability over 2300 h at 0.1 mA cm−2 and a remarkable cycle durability with 92.5 % of capacity retained after 570 cycles at 2C is also achieved for Li||LFP battery. This study provides a novel guidance in engineering solid electrolyte with excellent ionic transport kinetics and interfacial compatibility for next-generation SSLMBs.

Size effects of polydopamine-coated BaTiO3 nanoparticles on the piezoelectric performance of P(VDF-TrFE)/BaTiO3 composite

The size effect of the polydopamine (PDA)-coated BaTiO3 (BTO) (BTO@PDA) nanoparticles (NPs) on the interfacial compatibility between BTO NPs and the polymer matrix and the resultant piezoelectric performance of the composite films remain elusive. In this study, BTO and BTO@PDA NPs of various sizes were incorporated into a P(VDF-TrFE) matrix to prepare two series of P(VDF-TrFE)/BTO and P(VDF-TrFE)/BTO@PDA composites. Subsequently, the effects of the NP size on the dielectric, ferroelectric, and piezoelectric properties of the composite films were comprehensively studied. As the size of the BTO@PDA NPs increased, residual hole defects were clearly observed in the cross section of the composite film. The deteriorated interfacial compatibility due to the large size of the BTO@PDA NPs was also confirmed by the increased dielectric permittivity of the composite film, which was induced by the intensified interfacial polarisation. The P(VDF-TrFE)/BTO@PDA composite with NPs of the smallest size (100 nm) exhibited superior piezoelectric performance owing to the excellent interfacial compatibility between the fillers and the matrix. The piezoelectric performance was significantly enhanced by the reduced leakage current during electrical poling and reduced trap charges. Finally, the pulse waveform originating from the radial artery was precisely measured using the optimised P(VDF-TrFE)/BTO@PDA composite film.

A green organic-inorganic PAbz@ZIF hybrid towards efficient flame-retardant and smoke-suppressive epoxy coatings with enhanced mechanical properties

Developing sustainable bio-based flame retardants for flammable polymers has been a research trend. However, applying bio-based flame retardants to confer excellent flame retardancy, smoke suppression, and mechanical properties to polymers remains a formidable challenge. Herein, a green organic-inorganic hybrid (PAbz@ZIF) was readily prepared through a simple neutralization reaction and in-situ generation method and applied to fabricate high-performance flame-retardant epoxy coatings (EP-PAbz@ZIF). It has been shown that PAbz@ZIF hybrids can enhance the curing activity of epoxy coatings in addition to their excellent dispersibility and interfacial compatibility. In addition, the epoxy coating containing 5.0 wt% PAbz@ZIF (EP-5%PAbz@ZIF) exhibits a higher char yield (from 25.1 wt% to 31.5 wt%) in comparison to pristine epoxy resin (EP). More importantly, the PAbz@ZIF-based epoxy coatings show more efficient flame retardancy and smoke suppression compared to pristine EP. For instance, the 5.0 wt% PAbz@ZIF enables EP-5%PAbz@ZIF to obtain a satisfactory UL-94 rating of V0. Meanwhile, the peak heat release rate, total smoke production, peak CO production rate, and peak CO2 production rate of EP-5%PAbz@ZIF are remarkably decreased by 48.6%, 20.5%, 38.6%, and 56.7%, respectively. Furthermore, EP-5%PAbz@ZIF exhibits enhanced heat insulation performance, flexural strength, and impact strength. This work offers a feasible idea for designing green organic-inorganic PAbz@ZIF hybrids and fabricating high-performance flame-retardant epoxy coatings.

Innovative integration of pyrolyzed biomass into polyamide 11: Sustainable advancements through in situ polymerization for enhanced mechanical, thermal, and additive manufacturing properties

The incorporation of pyrolyzed biomass, i.e., biochar, in polymers can be viewed as a sustainable approach that reduces bio-waste in a smart way. Herein, various biochar concentrations were integrated into the biobased polyamide 11 (PA11) matrix via in situ polymerization. Scanning electron microscopy (SEM) micrographs demonstrated the homogeneous dispersion of up to 50 wt% biochar within the PA11 matrix, free from any phase separation, particle agglomeration, or crack formation. Consequently, there was a remarkable enhancement in mechanical and thermal properties. Notably, tensile strength and modulus increased by 35% and 72%, respectively, while the thermal decomposition process was significantly delayed with the incorporation of biochar particles. Furthermore, the viscoelastic performance of the PA11 matrix exhibited substantial improvement upon the addition of the filler particles. These impressive results verified the excellent interfacial compatibility achieved between the PA11 matrix and biochar, owing to the utilization of in situ polymerization. To demonstrate the potential application of these composites in additive manufacturing, a filament with a uniform diameter was fabricated from a composite comprising 50 wt% biochar. It was successfully employed in material extrusion to print a complex object. The resulting structure exhibited high shape fidelity, precise dimensions, and no noticeable defects. This groundbreaking strategy not only highlights the utilization of biochar as a sustainable filler but also underscores the efficacy of in situ polymerization in fabricating high-performance PA11/biochar composites for various demanding applications, including filament production for additive manufacturing.

Bamboo fiber strengthened poly(lactic acid) composites with enhanced interfacial compatibility through a multi-layered coating of synergistic treatment strategy

In this study, a mild and eco-friendly synergistic treatment strategy was investigated to improve the interfacial compatibility of bamboo fibers with poly(lactic acid). The characterization results in terms of the chemical structure, surface morphology, thermal properties, and water resistance properties demonstrated a homogeneous dispersion and excellent interfacial compatibility of the treated composites. The excellent interfacial compatibility is due to multi-layered coating of bamboo fibers using synergistic treatment involving dilute alkali pretreatment, polydopamine coating and silane coupling agent modification. The composites obtained using the proposed synergistic treatment strategy exhibited excellent mechanical properties. Optimal mechanical properties were observed for composites with synergistically treated bamboo fiber mass proportion of 20 %. The tensile strength, elongation at break and tensile modulus of the treated composites were increased by 63.06 %, 183.04 % and 259.04 %, respectively, compared to the untreated composites. This synergistic treatment strategy and the remarkable performance of the treated composites have a wide range of applicability in bio-composites (such as industrial packaging, automotive lightweight interiors, and consumer goods).

Straightforward Strategy Toward In Situ Water-Phase Exfoliation and Improved Interfacial Adhesion to Fabricate High-Performance Polypropylene/Graphene Nanocomposites.

Graphene is a potential candidate for achieving high-performance and multifunctional polypropylene (PP) composites. However, the complex manufacturing process and low dispersibility of graphene, as well as poor interfacial adhesion between graphene and polypropylene chains, stifle progress on large-scale production and applications of graphene/polypropylene composites. Here, we develop a strategy of maleic anhydride grafted polypropylene (MAPP) latex-assisted graphene exfoliation and melt blending to address the key challenges facing in industrial production. The surface property of the graphitic precursor is well-designed to achieve a high graphene exfoliation yield of ∼100% and induce abundant hydrogen bonding between the obtained mild-oxidized graphene (MOG) sheets and MAPP chains. Therefore, the MAPP-modified MOG can homogeneously disperse in the PP matrix and exhibits an excellent interfacial compatibility with the polymer. The addition of 5 wt % MOG results in simultaneous increase in the initial decomposition temperature, crystallization temperature, tensile strength, and Young's modulus by 43.2, 11.4 °C, 21.5, and 50.7%, respectively, and the electrical conductivity increases to 0.02 S·m-1. This work illustrates a practical solution to low-cost, eco-friendly, and feasible industrial production of graphene/PP composites through synchronous exfoliation and interfacial modification of graphene.

Progress and perspectives of in situ polymerization method for lithium‐based batteries

AbstractThe application of lithium‐based batteries is challenged by the safety issues of leakage and flammability of liquid electrolytes. Polymer electrolytes (PEs) can address issues to promote the practical use of lithium metal batteries. However, the traditional preparation of PEs such as the solution‐casting method requires a complicated preparation process, especially resulting in side solvents evaporation issues. The large thickness of traditional PEs reduces the energy density of the battery and increases the transport bottlenecks of lithium‐ion. Meanwhile, it is difficult to fill the voids of electrodes to achieve good contact between electrolyte and electrode. In situ polymerization appears as a facile method to prepare PEs possessing excellent interfacial compatibility with electrodes. Thus, thin and uniform electrolytes can be obtained. The interfacial impedance can be reduced, and the lithium‐ion transport throughput at the interface can be increased. The typical in situ polymerization process is to implant a precursor solution containing monomers into the cell and then in situ solidify the precursor under specific initiating conditions, and has been widely applied for the preparation of PEs and battery assembly. In this review, we focus on the preparation and application of in situ polymerization method in gel polymer electrolytes, solid polymer electrolytes, and composite polymer electrolytes, in which different kinds of monomers and reactions for in situ polymerization are discussed. In addition, the various compositions and structures of inorganic fillers, and their effects on the electrochemical properties are summarized. Finally, challenges and perspectives for the practical application of in situ polymerization methods in solid‐state lithium‐based batteries are reviewed.

Facile fabrication of novel fire-safe MXene@IL-based epoxy nanocomposite coatings with enhanced thermal conductivity and mechanical properties

In recent years, developing high-performance epoxy nanocomposite coatings with excellent fire safety, thermal conductivity, and mechanical performance has become a thorny challenge. Here, the multifunctional nanohybrid (MXene@IL) was facilely fabricated by an electrostatic self-assembly strategy, and epoxy nanocomposite coatings based on MXene@IL (EP/MXene@IL) were prepared. It has been found that MXene@IL nanohybrids exhibit excellent dispersion and interfacial compatibility in the epoxy matrix. Notably, the 2.0 wt% MXene@IL endows the epoxy nanocomposite coating with high fire safety, with a 43.76 % reduction in peak heat release rate and a 65.99 % reduction in smoke factor compared to virgin epoxy resin (EP), respectively. Meanwhile, the thermal conductivity (increased by 21.56 %) of EP/MXene@IL-2.0 is enhanced. Furthermore, the flexural and impact strengths of EP/MXene@IL-1.0 are improved by 10.24 % and 44.73 %, respectively. Interestingly, MXene@IL acts as a co-curing agent to facilitate the curing reaction of epoxy nanocoatings. This work provides a feasible strategy for designing multifunctional MXene@IL-based epoxy nanocomposite coatings.

Biomimetic construction of hierarchical MXene@PDA@CoFeOx nanohybrids towards efficient fire-safe epoxy nanocomposites with enhanced thermal conductivity and mechanical properties

Developing high-performance MXene-based polymer nanocomposites through a biomimetic method has been a research hotspot. However, it is still an intractable challenge to achieve MXene-based polymer nanocomposites with efficient fire safety, excellent thermal conductivity, and enhanced mechanical properties. Here, inspired by the adhesion of mussels, the hierarchical MXene@PDA@CoFeOx nanohybrid was fabricated by a self-assembly strategy and then employed to prepare epoxy resin (EP) nanocomposites. It has been found that MXene@PDA@CoFeOx can display excellent dispersion and interfacial compatibility in EP matrix. Thermogravimetric analysis shows that only 2.0 wt% MXene@PDA@CoFeOx results in excellent thermal stability and char yield (31.29 wt%) of EP under a nitrogen atmosphere. Combustion tests show that the 2.0 wt% MXene@PDA@CoFeOx confers efficient fire safety to EP. Remarkably, the EP-2.0%MXene@PDA@CoFeOx can obtain an attractive UL-94 rating of V0. Meanwhile, the peak heat release rate (pHRR), smoke factor (SF), and peak CO production rate (pCO) of EP-2.0%MXene@PDA@CoFeOx are dramatically decreased by 33.38%, 55.41%, and 36.84% in comparison to those of virgin EP, respectively. The efficient fire safety of EP nanocomposites is mainly attributed to the barrier effect, dilution effect, and catalytic carbonization effect of hierarchical MXene@PDA@CoFeOx. Furthermore, the MXene@PDA@CoFeOx enables EP to boast enhanced thermal conductivity (improved by 69.14%), impact strength (improved by 13.38%), and flexural strength (improved by 17.60%). This work offers a feasible biomimetic method for fabricating hierarchical MXene@PDA@CoFeOx nanohybrids and preparing efficient fire-safe EP nanocomposites with excellent thermal conductivity and mechanical performance.

A gradient “Ceramic-in-Ionogel” electrolyte with tidal ion flow for ultra-stable lithium metal batteries

Composite solid-state electrolytes are considered as key components for safe and high-energy-density lithium metal batteries, given their superior mechanical properties and ion conductive kinetics. However, it still remains a challenge to simultaneously guarantee high ionic conductivity and excellent interfacial compatibility. Herein, a gradient “Ceramic-in-Ionogel” electrolyte with tidal ion flow is proposed for decoupling ionic conductivity and interfacial property. It is composed of poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP))/EMIMTFSI/Al2O3 (30 wt. %) layer (Ionogel-dual30) toward cathode and P(VDF-HFP)/EMIMTFSI/Al2O3 (50 wt. %) layer (Ionogel-dual50) to Li-metal anode. Ionogel-dual50 can provide a relatively large number of Al2O3 particles for the formation of AlF3 and Li3AlF6 after being offered electrons at lithium-metal anode and carbon-fluorine bond cleavage in TFSI-, resulting in rapid Li+ transfer and insulated electron transport at interface. Both simulation and experimental characterization suggest that the tidal-flow-like ion transport pathway can offer [Li+-NMP]-P(VDF-HFP) dominant pathway in Ionogel-dual30 and [Li(TFSI)x]+-Al2O3 interface dominant pathway in Ionogel-dual50, achieving a high ionic conductivity of 0.25 mS cm−1. Benefiting from these unique merits, the cycling performance of symmetric Li batteries was greatly improved with a lifetime of over 1000 h at 0.1 mA h cm−2. The effect of this gradient ionogel electrolyte could be well demonstrated in various full cells, evidenced by substantially enhanced cyclability under large current density (2 C), wide voltage range (3–4.5 V) and extreme conditions. This novel “Ceramic-in-Ionogel” electrolyte with tidal ion flow will accelerate the commercialization of high-energy-density lithium metal batteries.

Polythiourea Superionic Conductors for Solid-State Batteries

Polymer electrolytes are considered as solid-state ionic conductors for the next generation of lithium metal batteries. Particularly, poly(ethylene oxide)-based electrolytes have been extensively studied due to their excellent ion conductivity and interfacial compatibility. Since the lithium-ion transport is strongly coupled with segmental motion of polymer chains, there usually exists a dilemma between the ion conductivity and mechanical strength enhancement. Other problems of low ion conductivity at low temperature and low cation transference number further impede their practical applications in batteries. Here, we report a type of polythiourea solid-state electrolyte, which exhibits a superionic ion conducting behavior. The strong supramolecular interaction between the thiourea group and perchlorate anions promotes the dissolution of high concentration lithium salts in polythiourea. The conducting channel composed of high-density thiourea and percolating polar groups enables rapid cation transport along the polymer chain and even working at the glass state. The combined merits of high transference number, good ion conductivity, and excellent mechanical strength are achieved in this class of superionic ionic conductors, shedding light on alternative solutions for solid-state electrolytes in batteries.

A LaCl3-based lithium superionic conductor compatible with lithium metal.

Inorganic superionic conductors possess high ionic conductivity and excellent thermal stability but their poor interfacial compatibility with lithium metal electrodes precludes application in all-solid-state lithium metal batteries1,2. Here we report a LaCl3-based lithium superionic conductor possessing excellent interfacial compatibility with lithium metal electrodes. In contrast to a Li3MCl6 (M=Y, In, Sc and Ho) electrolyte lattice3-6, the UCl3-type LaCl3 lattice has large, one-dimensional channels for rapid Li+ conduction, interconnected by Lavacancies via Ta doping and resulting in a three-dimensional Li+ migration network. The optimized Li0.388Ta0.238La0.475Cl3 electrolyte exhibits Li+ conductivity of 3.02 mS cm-1 at 30 °C and a low activation energy of 0.197 eV. It also generates a gradient interfacial passivation layer to stabilize the Li metal electrode for long-term cycling of a Li-Li symmetric cell (1 mAh cm-2) for more than 5,000 h. When directly coupled with an uncoated LiNi0.5Co0.2Mn0.3O2 cathode and bare Li metal anode, the Li0.388Ta0.238La0.475Cl3 electrolyte enables a solid battery to run for more than 100 cycles witha cutoff voltageof 4.35 V and areal capacity of more than 1 mAh cm-2. We also demonstrate rapid Li+ conduction in lanthanide metal chlorides (LnCl3; Ln=La, Ce, Nd, Sm and Gd), suggesting that the LnCl3 solid electrolyte system could provide further developments in conductivity and utility.

Two-step sintering of sulfide solid electrolyte with improved electrochemical properties for all-solid-state lithium batteries

All-solid-state batteries are considered as a promising energy storage system thanks to the high energy density and intrinsic safety. Sulfide solid electrolytes, a key component, are of interest owing to their high ionic conductivity and wide electrochemical windows. However, it remains a great challenge to simultaneously improve the ionic conductivity and the ability to inhibit lithium dendrites. Here, we report a strategy to obtain sulfide solid electrolyte with excellent interfacial compatibility and the high ionic conductivity via two-step sintering. The obtained electrolyte possesses excellent interfacial compatibility with lithium metal (>1000 h) and improved critical current density (1.05 mA cm−2). Meanwhile, the all-solid-state batteries deliver a high discharge capacity of 160 mA h g−1 with excellent stability of 90.4% after 100 cycles at 0.1 C at room temperature. This study provides a novel and effective strategy for tuning the properties of sulfide electrolyte and promotes the practical application in sulfide-based all-solid-state batteries.

LiNO3-Assisted Succinonitrile-Based Solid-State Electrolyte for Long Cycle Life toward a Li-Metal Anode via an In Situ Thermal Polymerization Method.

Succinonitrile (SN)-based electrolytes have a great potential for the practical application of all-solid-state lithium-metal batteries (ASSLMBs) due to their high room-temperature ionic conductivity, broad electrochemical window, and favorable thermal stability. Nevertheless, the poor mechanical strength and low stability toward Li metal hinder the further application of SN-based electrolytes to ASSLMBs. In this work, the LiNO3-assisted SN-based electrolytes are synthesized via an in situ thermal polymerization method. With this method, the mechanical problem is negligible, and the stability of the electrolyte enhances tremendously toward Li metal due to the addition of LiNO3. The LiNO3-assisted electrolytes exhibit a high ionic conductivity of 1.4 mS cm-1 at 25 °C, a wide electrochemical window (0-4.5 V vs Li+/Li), and excellent interfacial compatibility with Li (stable for over 2000 h at a current density of 0.1 mA cm-1). The LiFePO4/Li cells with the LiNO3-assisted electrolytes present significantly enhanced rate capability and cycling performance compared to the control group. NCM622/Li batteries also exhibit good cycling and rate performances with a voltage range of 3.0 to 4.4 V. Furthermore, ex situ SEM and XPS are employed. A compact interface is observed on Li anode after cycling, and the polymerization of SN is found to be suppressed. This paper will promote the development of practical application of SN-based ASSLMBs.

Preparation of polyacrylamide/calcium alginate@Ti3C2Tx composite hydrogels with high adhesive performance for flexible supercapacitor electrolytes

Polymer hydrogels are a promising electrolyte for flexible superconductors (FSCs) due to their excellent flexibility, ions transportations and interfacial compatibility. However, the large internal resistance will decrease the power density (PD) and energy density (ED) of FSCs. In this work, Ti3C2Tx was introduced to polyacrylamide/calcium alginate (PC) hydrogel electrolyte to decrease the internal resistance (IR) and improve the interfacial adhesion. The polyacrylamide/calcium alginate@Ti3C2Tx (PCT) composite hydrogels were successfully prepared by in-situ polymerization. Their mechanical property and adhesive property to various substrates were investigated, respectively, and a flexible supercapacitor was assembled with composite hydrogels as electrolyte and two self-made Ti3C2Tx sheets as electrode. It was found composite hydrogels can adhere to various substrates, which make the voltage drop of FSCs from 163 mV to 78.9 mV. The FSCs show a good performance, whose specific capacitance is 1051.9 mF cm−2 with a current density of 1.07 mA cm−2, and the ED reaches 32.3 Wh kg−1 and the capacitance retention rate is as high as 96% at a high current density of 18.7 mA cm−2. Meanwhile, it can sensitively monitor human movements such as finger bending, frowning, swallowing, etc. This work is expected to be applied in the field of energy storage and sensing.

Lipoic Acid-Assisted In Situ Integration of Ultrathin Solid-State Electrolytes

Ultrathin solid-state electrolytes (SSEs) have contributed to high-energy-density lithium-ion batteries (LIBs). However, when reducing thickness of SSEs, mechanical properties will inevitably deteriorate, even increasing the safety hazards. In this work, we developed an in-situ integration strategy to form an ultrathin SSE by combining a lipoic acid-assisted semi-interpenetrating polymer network and an ultrathin porous membrane. With this strategy, the thickness of the obtained SSE (named LA-SSE) is only 10 μm, and the LA-SSE possesses extraordinary mechanical performances to suppress the growth of lithium dendrites. Meanwhile, the flexible LA-SSE presents anionic conductivity of 0.036 mS cm–1 and promotes interfacial compatibility between the lithium anode and the electrolyte. By employing LA-SSE as the electrolyte, the assembled Li∥LA-SSE∥Li symmetric cell operated with long-term cycling (more than 3000 h), and the LiFePO4∥LA-SSE∥Li full battery worked steadily over 200 cycles at 0.5 C with a capacity retention of 84% at room temperature. This work provides a promising strategy for designing ultrathin SSEs, with satisfactory mechanical properties, excellent interfacial compatibility, and safety, for LIBs.

Biomass tannic acid intermediated surface functionalization of ammonium polyphosphate for enhancing fire safety and smoke suppression of thermoplastic polyurethane

Hierarchical ammonium polyphosphate (HAPP) was designed and fabricated by means of a simple strategy. FeOOH nanoparticles were decorated onto the APP surface based on the universal surface-adaptive interfacial adhesion of tannic acid (TA) and then modified by using polydimethylsiloxane (PDMS) to obtain HAPP. Owing to unique microstructure, the introduction of HAPP not only endows thermoplastic polyurethane (TPU) with admirable flame retardancy, but also presents excellent interfacial compatibility. The Young’s modulus, tensile strength and elongation at break of TPU composite with 5 wt% HAPP are increased by 4.3 %, 11.0 % and 16.6 %, respectively, relative to the values for TPU composite containing 5 wt% APP. Furthermore, TPU composite including 5 wt% HAPP achieve a UL-94 V-0 rating with the maximum limiting oxygen index value. Compared to those of TPU, the peak heat release rate, total heat release and total smoke production of TPU composite with 5 wt% HAPP are remarkably decreased with the reduction of 57.7 %, 23.1 % and 82.3 %, respectively. The proposed combination of transition metal oxides and low surface energy material is expected to reinforce the interfacial adhesion force between the APP and the polymer matrix and then inspires new strategies to construct polymer composites with excellent comprehensive properties.