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The electrochemical stability window of the electrolyte solution limits the energy content of non-aqueous lithium metal batteries. In particular, although electrolytes comprising fluorinated solvents show good oxidation stability against high-voltage positive electrode active materials such as LiNi0.8Co0.1Mn0.1O2 (NCM811), the ionic conductivity is adversely affected and, thus, the battery cycling performance at high current rates and low temperatures. To address these issues, here we report the design and synthesis of a monofluoride ether as an electrolyte solvent with Li-F and Li-O tridentate coordination chemistries. The monofluoro substituent (-CH2F) in the solvent molecule, differently from the difluoro (-CHF2) and trifluoro (-CF3) counterparts, improves the electrolyte ionic conductivity without narrowing the oxidation stability. Indeed, the electrolyte solution with the monofluoride ether solvent demonstrates good compatibility with positive and negative electrodes in a wide range of temperatures (i.e., from −60 °C to +60 °C) and at high charge/discharge rates (e.g., at 17.5 mA cm−2). Using this electrolyte solution, we assemble and test a 320 mAh Li||NCM811 multi-layer pouch cell, which delivers a specific energy of 426 Wh kg−1 (based on the weight of the entire cell) and capacity retention of 80% after 200 cycles at 0.8/8 mA cm−2 charge/discharge rate and 30 °C. The energy content of non-aqueous lithium batteries is limited by the electrochemical stability window of the electrolyte solution. Here, the authors report a monofluoride ether-based electrolyte to stabilize high-voltage lithium metal batteries at high current rates and low temperatures. [ABSTRACT FROM AUTHOR]

Solid polymer electrolyte with good thermal stability and flexibility is an excellent candidate for solid‐state lithium metal batteries, while its low ionic conductivity caused by high crystallinity limits its application at ambient temperature. Here a metal organic framework (zeolitic imidazolate framework‐8, ZIF‐8) composited comb‐like methoxy poly(ethylene glycol) acrylate polymer electrolyte (MCPE) with high ionic conductivity (9.96 × 10−5 S cm−1 at 30 °C) is prepared by an in situ UV polymerization method. The as‐prepared MCPE exhibits improved mechanical property due to the introduction of porous ZIF‐8 nanofillers, which is beneficial to suppress the growth of lithium dendrites. Consequently, the LiFePO4||MCPE||Li cells show a high capacity of 116 mAh g−1 at 30 °C and 0.5 C, and maintain 89.4% of initial capacity after 150 cycles with the average Coulombic efficiency of 99.9%. These results demonstrate that the MCPE shows great potential in solid‐state lithium metal batteries near room temperature. [ABSTRACT FROM AUTHOR]

The solution behavior and molecular conformation of sodium lignosulfonates (NaLS) in saline solution has been studied by means of static and dynamic light scattering (LSstat and LSdyn). Results show that the salt content must be larger to eliminate the slow mode in LSdyn analysis of NaLS than that of the theory, and this discrepancy can only be explained by a modified microgel model. The higher salt amount is needed for the formation of a strong ionic gradient field between surface and the inner part of NaLS, which forces counter ions to penetrate into the inner part of NaLS to screen the small amount of charges. The NaLS single molecular shape can be described by an oblate spheroid based on the absolute molecular weight Mw and diffusion coefficients D. The best fitting result is semiaxis a=1.6 nm and axial ratio r=3.5, D=5.73×10-7 cm2 s-1, and the corresponding Mw=1.7×105 g mol-1. [ABSTRACT FROM AUTHOR]

Sodium lignosulfonate (NaLS) was dissolved in saline solutions, and the dissolving process was examined by a combination of static and dynamic light scattering. When NaLS was dissolved in 1.2 mol l-1 NaCl solution for 24 h and filtered through a 0.45 μm syringe filter, only a fast relaxation mode was observed, which was attributed to the co-diffusion of NaLS molecular ions and counterions. When the concentration of NaCl was below 1.2 mol l-1 or the dissolving time was <24 h, an additional slow relaxation mode (SRM) appeared due to hindered motions of electrostatically interacting chains. Without filtering or filtering followed by rising temperature to 38°C, SRM appeared due to aggregation, which occurred at a position similar to that caused by electrostatic interaction. For poly(sodium styrenesulfonate) (NaPSS) and modified bamboo lignin derivate with open polyelectrolyte structures, 0.1 mol l-1 NaCl was enough to inhibit the electrostatic interaction. For NaLS with a closed polyelectrolyte structure, the SRM could not be removed until the concentration of NaCl reached 1.2 mol l-1. Above observations give insights for the first time into the relationship between the SRM caused by electrostatically interacting chains and the diffusion mode due to NaLS aggregation, and the influence of the closed polyelectrolyte structure on the SRM. [ABSTRACT FROM AUTHOR]

The problems related to the determination of the absolute molecular weight ( Mw) of sodium lignosulfonate (NaLS) are the focus of the present work. Four narrow-dispersed NaLS fractions were collected by filtration, ultrafiltration, and gel permeation chromatography (GPC), and their Mw measured by laser light scattering (LLS Mw) was compared with that obtained by GPC (GPC Mw). The LLS Mw values were much larger than GPC Mw, and this Mw difference increased with increasing Mw of NaLS. This finding confirms the known polyelectrolyte and aggregation effects of NaLS. The deviation is also partly due to the conformation differences between the GPC standard (sodium polystyrene sulfonate) and the NaLS molecules. The effects of polyelectrolytes and NaLS aggregates could be inhibited by adding enough NaCl salt in the NaLS solution and filtering the NaLS/NaCl solution through a syringe filter. As a result, the slow mode in dynamic LLS measurement disappeared. By this approach, the absolute LLS Mw values were only slightly larger than that determined by GPC due to the conformation differences between the GPC standard and the NaLS molecules. [ABSTRACT FROM AUTHOR]

Gel polymer electrolytes (GPEs) hold great promise for lithium (Li) metal batteries (LMBs). Nevertheless, a critical challenge lies in reducing the thickness of GPEs while maintaining their mechanical integrity to achieve high‐energy‐density LMBs. Additionally, protecting the Li metal anode via electrolyte engineering in GPEs remains demanding. Herein, an innovative ultrathin (1 µm‐thick) yet robust GPE developed using an in situ curing technique, featuring a nanofibrous, exceptionally strong polyethylene separator is presented. The unique microstructure, interfacial conformability, and ultrahigh mechanical robustness of the ultrathin polyethylene separator are thoroughly verified. Enhanced ionic association within the GPE is achieved due to the strong affinity of electrolyte solvent with the fluorinated polymer network, as confirmed by large‐scale molecular dynamics simulations. The optimized solvation structure with high contact ion pairs and aggregate fractions contributes to forming an anion‐derived inorganic‐rich solid electrolyte interphase (SEI), thereby protecting the lithium anode. Benefiting from the ultrahigh robustness of GPE and the excellent interfacial stability, the Li metal full cell with a high mass loading LiNi0.8Co0.1Mn0.1O2 cathode (≈17.3 mg cm−2) and thin Li foil anode (50 µm) demonstrates 91% capacity retention after 200 cycles. This design demonstrates a feasible approach toward the practical quasi‐solid‐state LMBs. [ABSTRACT FROM AUTHOR]

Nano-sized fillers in a polymer matrix with good distribution can play a positive role in improving polymer electrolytes in the aspects of ionic conductivity, mechanical property and electrochemical performance of Li-ion cells. Herein, polyethylene oxide (PEO)/Li 3 PS 4 hybrid polymer electrolyte is prepared via a new in-situ approach. The ionic conductivities of the novel hybrid electrolytes with variable proportions are measured, and the optimal electrolyte of PEO-2%vol Li 3 PS 4 presents a considerable ionic conductivity of 8.01 × 10 −4  S cm −1 at 60 °C and an electrochemical window up to 5.1 V. The tests of DSC and EDXS reveal that the Li 3 PS 4 nanoparticles with better distribution, as active fillers scattering in the PEO, exhibit a positive effect on the transference of lithium ion and electrochemical interfacial stabilities. Finally, the assembled solid-state LiFePO 4 /Li battery presents a decent cycling performance (80.9% retention rate after 325 cycles at 60 °C) and excellent rate capacities with 153, 143, 139 and 127 mAh g −1 at the discharging rate of 0.1 C, 0.2 C, 0.5 C and 1 C at 60 °C. It is fully proved that it is an advanced strategy to preparing the new organic/inorganic hybrid electrolytes for lithium-ion batteries applications. [ABSTRACT FROM AUTHOR]

Adsorption and desorption of biomolecules on/from polyelectrolyte surfaces play a critical role in numerous biomedical and engineering applications. Though some weak polyelectrolytes have been developed for protein adsorption and desorption by regulating the salinity and pH, limited reports are available about the regeneration of strong polyelectrolyte surfaces between protein-attractive and protein-repulsive states, which is highly desirable but challenging to realize as it is more difficult to fully release the pre-adsorbed proteins from strong polyelectrolytes due to their permanent charges comparing to weak polyelectrolytes. Here we report a strategy to facilely tune the resistance to nonspecific protein adsorption onto a charged cationic poly([2-(methacryloyloxy) ethyl] trimethylammonium chloride (PMTAC) or anionic Poly(3-sulfopropyl methacrylate potassium salt) (PSPMA)) strong polyelectrolyte brush coating via salinity adjustment. It has been demonstrated that the charged polyelectrolyte coating displays strong adhesion to proteins at low salinity (e.g., 0.1 mM NaCl) but protein-repellent property at high salinity (e.g., 1.0 M NaCl). The adsorbed proteins on the strong polyelectrolyte coatings under low salinity condition could be readily removed via rinsing with high-salinity water, demonstrating the excellent surface regeneration capability. [ABSTRACT FROM AUTHOR]

In this work, poly (methyl vinyl ether-alt-maleic anhydride) abbreviated as P(MVE-MA) is employed as an ecofriendly electrolyte additive for stabilizing the interface of high-voltage layered Li-rich oxides (LLROs) without sacrificing performance. By the addition of 1 wt. % P(MVE-MA), the capacity retention of the Li-rich oxides at 250 mA g−1 for 300 cycles in the voltage range of 2.5–4.6 V is significantly improved from 38.6% to 77.2%, and the retained specific discharge capacity is as high as 159 mAh g−1. It is also found that the voltage decay and resistance increase during cycling are both suppressed noticeably because that the addition of P(MVE-MA) suppresses electrolyte degradation. Based on various characterizations, P(MVE-MA) mainly has two functions: one is to decrease the H 2 O and HF contents in the electrolyte due to the hygroscopic property of anhydride; and the other is to form thin and stable polymer cathode electrolyte interphase (CEI) on LLROs because of its strong adhesive ability to the cathode. Therefore, the side reactions and structural degradation of LLROs are mitigated distinctly, improving the electrochemical performance of LLROs. Considering its effective and ecofriendly performance for high-voltage LLROs, P(MVE-MA) is believed to be positive for other high-voltage cathode materials. [Display omitted] [ABSTRACT FROM AUTHOR]

• Flexible solid-state cells are developed with an in situ integration strategy. • A 20-µm-thick hybrid polymer/ceramic/ionic liquid electrolyte is prepared. • Stable interfaces are built, keeping intimate contact and reducing resistance. • The Li 4 Ti 5 O 12 /LiNi 0.8 Co 0.1 Mn 0.1 O 2 cell exhibits long cycling life at 30 °C. • The use of Si-based anode achieves 489.6 Wh kg−1 energy density at material's level. Flexible solid-state batteries (FSSBs) are indispensable energy storage devices to fulfil the energy and safety requirements for future flexible applications. The bottlenecks of FSSBs are how to realize high energy density with competent ionic conductivity for room-temperature (RT) flexible applications. Here, the first fabrication of RT FSSB with high energy density is reported, which is realized by in situ integration of a 20-µm-thick hybrid polymer/ceramic/ionic liquid solid-state electrolyte (SSE) between the high energy combination of anode/cathode electrodes. The in situ electrode/electrolyte interfacial integration strategy provides an ultrathin SSE layer, ultralow resistance and superior flexibility, and the SSE guarantees both high ionic conductivity and good compatibility with high-energy cathode LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811). The fabricated Li 4 Ti 5 O 12 /NCM811 FSSB delivers super-low resistance approaching conventional liquid cells and excellent cycling stability up to 600 cycles at RT. The extension of anode to SiO x @graphite leads to a high theoretical energy density of 489.6 Wh kg−1 at material's level, times higher than current options. In addition, the RT FSSB shows great flexibility, indicating a high performance application in future flexible electronics. [ABSTRACT FROM AUTHOR]

Abstract: In this study, multilayer films composed of alternate polyaniline (PANI) and azo-polyelectrolyte (PNACN, PPAPE, PNANT or PNATZ) layers were fabricated through the electrostatic layer-by-layer self-assembly scheme. In the electrostatic adsorption process, PANI was used as the polycation and the azo polyelectrolytes were used as the polyanion. The multilayer growth was monitored by UV–vis spectroscopy and optical ellipsometry. The photoresponsive and electrochromic properties of the multilayer films were studied by UV–vis spectroscopy and electrochemical measurement. Results show that the multilayer films exhibit linear increases in both the absorbance and film thickness with the increase of the deposition cycles. The thickness contributed by each individual layer depends on the pH of the PANI and azo-polyelectrolyte dipping solutions. The multilayer films can show photoinduced dichroic properties contributed by the azo-polyelectrolyte layers, but the ability to form surface-relief-grating (SRG) upon Ar+ laser irradiation is relatively weak. The multilayer films possess the characteristic absorption bands related to the azo chromophores and PANI. As the location of the PANI bands depends on its oxidation states, the multilayer films can show sensitive electrochromic variation. For instance, the PANI/PNACN multilayer films can undergo a transition from transparent yellow-green through deep green to opaque black when the potential changes from −0.1 to 0.8V. It is demonstrated that using the azo polyelectrolytes with different hues, enriched spectrum of the colors can be obtained by the electrochemical transitions. The multilayer films containing both photoresponsive and electroactive components can be expected for applications in optics, photonic devices and others. [Copyright &y& Elsevier]

[Display omitted] • Zeolitic imidazolate framework-90 grafted with ionic liquid (ZIF-90-g-IL) was prepared. • Solid polymer electrolytes (SPEs) with ZIF-90-g-IL were obtained. • Composite SPEs showed high ionic conductivity and broad electrochemical stability window. • Composite SPEs could inhibit growth of lithium dendrites. • Li batteries with composite SPEs exhibited super-long cycle life at high rate. The stable structure, high porosity and surface functionality endow metal organic frameworks (MOFs) nanoparticles as excellent nanofillers for high-performance poly (ethyleneoxide)-based solid polymer electrolytes (PEO SPEs). However, the agglomeration of MOFs severely limits their potential applications. Herein, a novel zeolitic imidazolate framework-90 nanofiller grafted with imidazole ionic liquid containing siloxane groups (ZIF-90-g-IL) is prepared by dehydration condensation reaction, which enables the uniform distribution of the nanofiller in PEO SPEs. The resulting composite PEO SPE with ZIF-90-g-IL nanofillers delivers higher ionic conductivity of 1.17 × 10-4 S/cm at 30 °C and lithium ion transference number of 0.44, wider electrochemical stability window of 4.8 V, and stronger ability to inhibit lithium dendrite growth than the PEO SPE with unmodified ZIF-90. The strong interaction of ZIF-90-g-IL with PEO is caused by the chelation of quaternary ammonium cations of ionic liquid groups on the ZIF-90-g-IL surface with oxygen containing a lone pair of electrons of PEO, resulting in a uniform distribution of the nanofillers in PEO. The LFP||Li half cells with the PEO/ZIF-90-g-IL SPE exhibit good cycling performance with 71% capacity retention (101 mAh g−1) after 500 cycles at 2C under 60 °C, and show excellent cycling performance with 97.4% capacity retention (148 mAh g−1) after 30 cycles at 0.1C under 30 °C. The composite SPE is also used for high-voltage NCM811||Li half cells. The capacity retention is 63% (99 mAh g−1) after 100 cycles at 0.1C under 60 °C. The results imply ZIF-90-g-IL as effective nanofillers for SPEs showing a great potential application in all solid-state lithium metal batteries. [ABSTRACT FROM AUTHOR]

Solid polymer electrolytes (SPEs) shows increasing promise for all-solid-state batteries due to their high safety, high flexibility and low interfacial resistance. However, the low ionic conductivity at room temperature is the main barrier hindering the practical application of SPEs. Herein, hollow nanotubular clay composited comb-like methoxy poly(ethylene glycol) acrylate polymer electrolyte (HCPE) is fabricated by in-situ UV activated radical polymerization, which exhibits an improved ionic conductivity of 5.62 × 10−5 S cm−1 at room temperature. The introducing of the branched structure helps reduce the regularity of polymer chains and decreases the proportion of crystalline regions of polymers. Moreover, the nanofiller feature and the special structure of halloysite nanotube (HNT) are beneficial for dissociating lithium salt, thus improving the ionic conductivity. Meanwhile, the designed composite solid-state electrolyte demonstrates high thermal stability and compatibility with Li metal, high electrochemical stability. The all-solid-state Li/HCPE/LiFePO 4 cell delivers high rate capability and stable cycling performance at room temperature, which proves the great potential of HCPE for all-solid-state Li metal batteries. • A hollow nanotubular clay composited comb polymer is prepared. • The solid polymer electrolyte shows high conductivity and good thermal stability. • The solid polymer electrolyte exhibits broad electrochemical stability window. • The solid-state cell delivers high rate capability and good cycling performance. [ABSTRACT FROM AUTHOR]