Stable Cycling Performance Research Articles

Balancing high graphitization and porous structure in N-doped carbon lamella for effective sulfur host of Li[sbnd]S battery

Porous carbon synchronously with high conductivity and abundant porous structure is considered to be an effective sulfur host material for boosting the lithium-storage property in battery fields. Herein, a natural silk cocoon derived in-situ N-doping porous carbon lamella with ultrahigh graphitization degree is prepared by a facile synchronous carbonization and catalysis using the bimetallic mixed salts of FeCl3 and ZnCl2. The pore structure and graphitization degree are easily regulated by changing carbonization temperature to balance the synergistic adsorption and conversion actions toward the polysulfides adhered to porous carbon lamellar. When the carbon lamellar is used to design sulfur cathode, the abundant porous structure not only encapsulates active sulfur, but also facilitates electrolyte infiltration. The shuttle effect of polysulfides can be restrained by the synergistic adsorption of porous structure and N-doping. Especially, the ultrahigh graphitized carbon lamellas provide an excellent conductive network for the favorable redox conversion of polysulfide species during charge/discharge. Owing to the structure merits of the porous carbon lamella prepared at 1000 °C, the corresponding carbon/sulfur composite cathode delivers a first discharge capacity of 807.7 mAh g−1 at 0.2C. Even at a current rate of 1C, the stable long cycling performance of 1000 cycles is still maintained. This high graphitized porous carbon materials will provide potential application in other energy-storage fields.

Nanofluid channels mitigated Zn2+ concentration polarization prolonged over 30 times lifespan for reversible zinc anodes

Despite interfacial engineering protects zinc anode from electrolyte corrosion, the suppressed kinetics process on the anode surface/interface circumscribes their cyclic stability, especially dendritic growth induced by ion concentration gradients. Here, the zinophilic nanofluid channels (ZNC) protective layer on zinc surface are designed for the rapid Zn2+ transport kinetic in the reversible cycling process. The ZNC demonstrates high separation pressure between ions and the channel surface due to the capillary effect, allowing Zn2+ to quickly migrate along the channel wall (Zn2+ transference numbers up to 0.72). Therefore, the unique channel modules alleviate concentration polarization from rapid Zn2+ consumption and maintain uniform deposition of Zn ions. Consequently, The ZNC protective layer anode exhibits significantly improved cycle life by more than 30 times (over 4000 h at 1 mA cm−2) that of bare Zn. The full battery exhibits stable cycling performance with excellent capacity retention (∼100%) after 5000 cycles. Our work provides innovative insights into the role of nanofluids in improving the stability of zinc anodes, offering enlightening perspectives for long-cycle life zinc-based batteries.

Unveiling degradation mechanisms of anode-free Li-metal batteries

Anode-free Li-metal batteries (AFLMBs), in which Li+ ions from the cathode are deposited on a Cu substrate and the deposited Li-metal serves as the anode, exhibit higher energy density compared to Li-metal batteries (LMBs). However, achieving stable cycle performance, even at moderate operating conditions, is difficult and has so far hindered their practical uses. In AFLMBs, the homogeneity of solid electrolyte interphase (SEI), initially created by electrolyte reduction on Cu substrate, is not maintained during Li-metal deposition, leading to uncontrolled electrolyte decomposition. The SEI is therefore not conserved, and uneven Li deposition morphology is induced on the Cu substrate and the eventual instability of SEI leads to the overall degradation of AFLMBs. Here, we report on the failure mechanisms of AFLMBs through a comparative study with LMBs using 3 M lithium bis(fluorosulfonyl)imide (LiFSI) dissolved in N,N-dimethylsulfamoyl fluoride. Our investigation reveals that the SEI inhomogeneity in AFLMBs makes Li+ transport through SEI sluggish and non-uniform, triggering local compositional changes of the initially formed SEI on the Cu substrate and unwanted consumption of FSI– anion from the electrolyte. This work provides clear understanding to the interfacial engineering and important roles of Li-metal on the Cu substrate in AFLMBs, promising the creation of stable SEI, reversible electrochemical reaction of Li-metal, and interfacial stability of the cathode in LMBs.

Innovative Multielement Modification of Pitch-Derived Two-Dimensional Carbon Nanosheets as Anodes for Superior Performance Sodium-Ion Batteries.

The development of advanced anode materials for sodium-ion batteries (SIBs) using pitch-based carbon materials has the advantages of low cost, high electrical conductivity and easy structural modification. In this research, various well-established modification techniques for petroleum pitch are integrated, including the use of recrystallized NaCl as molten salt template, pretreatment and high-temperature carbonization under a pure oxygen atmosphere, and the introduction of heteroatoms (N and S) by hydrothermal methods. The resulting two-dimensional carbon nanosheets with multielement modification exhibit enhanced Na+ storage properties, thereby bringing higher cycling stability and superior rate performance. Due to its specific structure and chemical composition, NS-P-OPDC exhibited a high reversible capacity of 406.77 mAh g-1 at a current density of 100 mA g-1 and a superior rate performance of 193.20 mAh g-1 at a current density of 3 A g-1 after being applied to the anode of SIB half-cell. Especially, a capacity retention of 97.7% was still achieved after 4000 cycles. Meanwhile, the full-cell assembled by Na3V2(PO4)3 (NVP) cathode and NS-P-OPDC anode could provide a reversible capacity of 235.30 mAh g-1 at a current density of 300 mA g-1. This application proves to advance petroleum pitch-based high-performance electrodes toward greater efficiency in electrochemical energy storage.

An Organic Small Molecule Electrode with Intermolecular Intercalation and Synergistic Effects for High‐Rate Alkali Metal‐Ion Batteries

AbstractDesignable molecular structures, unique ion‐coordination charge storage mechanisms, and resource sustainability enable organic electrode materials to become potential candidates for alkali metal‐ion batteries (AMIBs). Herein, integrating the excellent π–π stacking ability of Hexaazatriphenylene units and strong electron‐withdrawing properties of cyano (C≡N) groups into one moleuce, a π‐conjugated organic compound 1,4,5,8,9,11‐Hexaazatriphenylenehexacarbonitrile (HAT‐CN) is synthesized and systematically investigated as electrodes in Li/Na/K‐ion batteries. Explored by mechanism characterizations and density functional theory calculations, HAT‐CN can provide nine redox‐active sites for Na/K‐ions to intercalate/de‐intercalate, among which six Na/K‐ions are distributed evenly to both sides of conjugated skeletons through intermolecular intercalation and three Na/K‐ions are stored with the synergistic effect of C≡N groups. Employing HAT‐CN as electrodes, AMIBs are found to exhibit high reversible capacities, excellent rate capabilities, and stable cycle performances. After 100 cycles at the current density of 100 mA g−1, Na‐ion batteries present 415.6 mAh g−1 with a capacity fading rate of 1.2% per cycle. Meanwhile, K‐ion batteries maintain 345 mAh g−1 with a coulombic efficiency ≈100%. Li‐ion batteries display superlithiation performances with ultra‐high reversible capacity. This work emphasizes the necessity of comprehensively studying the electrochemical performance of organic electrodes in different secondary battery systems and is conducive to maximizing electrode functionality.

Metal‐Organic Framework Hosted Silicon for Long‐Cycling, Low‐Cost, and Flexible Batteries

AbstractDeveloping biodegradable electrodes is a significant step toward environmental sustainability and cost reduction in battery technology. This paper presents a new approach that utilizes metal‐organic framework (MOF)‐encapsulated silicon nanoparticles (SiNPs) as the active anode material within a cellulose‐based electrode. The electrode is free‐standing, flexible, biodegradable, and significantly reduces the strain experienced by SiNPs during volume expansion, resulting in improved capacity and cycle life stability of SiNPs. The high porosity of the electrode creates efficient lithium (Li+) ion transport channels and enhances electrolyte absorption, thus promoting effective contact between the electrolyte and active material. The outcome is rapid electrode kinetics and a highly reversible discharge capacity of 1744.6 mAh g−1 at 0.5 A g−1 versus Li/Li+ over 1000 cycles. Further, full cell tests are conducted that demonstrate a stable cycle performance exceeding 3400 cycles, with an initial discharge capacity retention of 80.5% at 0.5 A g−1. By employing cellulose and avoiding toxic organic solvents and binders, the proposed approach is promising for a substantial reduction of the production costs of Li‐ion batteries. The scalability of the proposed method further enhances its practical viability, offering intriguing economic implications for the future of battery technology.

Tailoring Cationic Cobalt Vacancies in Molybdenum-Cobalt Selenide Derived from POM@ZIF-67 for Enhanced Electrocatalysis in Lithium-Oxygen Batteries.

Slow reaction kinetics during redox reactions limits the utilization of the high theoretical energy density of lithium-oxygen batteries (LOBs). Vacancy engineering, a potential strategy for modulating active sites, is critical in the development of high performance catalysts. This study investigates cobalt vacancies in Mo-CoSe2 nanoparticles created by selenization of phosphomolybdic acid (POM) embedded into zeolitic imidazolate framework-67 (ZIF-67). The nanomaterial exhibits an outstanding electrochemical performance, characterized by high specific capacitance and excellent cycle durability. The LOBs with cobalt vacancies in the Mo-CoSe2 electrode material exhibit a discharge capacity of 21 836 mAh g-1 at a current density of 100 mA g-1 and exhibit stable cycling performance over 194 cycles at 300 mA g-1. Additionally, density functional theory (DFT) calculations suggest that the presence of cobalt vacancies increases the distance between the surface selenium atoms and the subsurface cobalt atoms. In addition, cobalt vacancies modify the electronic structure of the d-orbitals, lowering the energy barriers of the reaction and accelerating the reaction kinetics by improving the adsorption of the reactants. The research introduces a strategy for the rational design of efficient cathode materials in LOBs.

A Supramolecular Deep Eutectic Electrolyte Enhancing Interfacial Stability and Solution Phase Discharge in Li−O2 Batteries

AbstractLi−O2 batteries (LOBs) have gained widespread recognition for their exceptional energy densities. However, a major challenge faced by LOBs is the lack of appropriate electrolytes that can effectively balance reactant transport, interfacial compatibility, and non‐volatility. To address this issue, a novel supramolecular deep eutectic electrolyte (DEE) has been developed, based on synergistic interaction between Li‐bonds and H‐bonds through a combination of lithium salt (LiTFSI), acetamide (Ace) and boric acid (BA). The incorporation of BA serves as an interface modification additive, acting as both Li‐bonds acceptor and H‐bonds donor/acceptor, thereby enhancing the redox stability of the electrolyte, facilitating a solution phase discharge process and improving compatibility with the Li anode. Our proposed DEE demonstrates a high oxidation voltage of 4.5 V, an ultrahigh discharge capacity of 15225 mAh g−1 and stable cycling performance of 196 cycles in LOBs. Additionally, the intrinsic non‐flammability and successful operation of a Li−O2 pouch cell indicate promising practical applications of this electrolyte. This research broadens the design possibilities for LOBs electrolytes and provides theoretical insights for future studies.

Highly interweaved carbonaceous interlayer synchronously decorated by foreign atoms and metals for adsorbing and catalyzing polysulfides in lithium-sulfur batteries

A highly interweaved carbonized bacterial cellulose (CBC) decorated by heteroatoms and metallic nanoparticles was fabricated through initial coating of a metallic coordination polymer onto BC nanofibers followed by carbonization. The carbonaceous CBC networks not only efficiently transfer electrons but also entrap the soluble polysulfides by physical interception. Moreover, the polar ingredients of foreign atoms and metals on CBC networks enable a favorable chemisorption toward polysulfides, and meanwhile the embedded metallic nanoparticles promote the conversion kinetics via electrocatalysis. Theoretical simulation and experimental investigation co-confirm that the decorated Ni species greatly enhance the adsorption capability towards polysulfides, as well as reduce the energy barrier of the rate-determining step via electrocatalysis. As a consequence, the lithium-sulfur batteries equipped with the optimal Ni-NCBC interlayer exhibited relatively high specific capacity (1245 mAh g−1 at 0.2 A g−1), superior rate capability (820 mAh g−1 at 4.0 A g−1), and stable cycling performance (73.2 % capacity retention after 1000 cycles). This work proposes a facile strategy to synchronously incorporate heteroatoms and metallic decorations into highly conductive nanofibrous networks for alleviating the shuttling effects of polysulfides effectively.

Tailoring the Wettability of Bacterial Cellulose Magnetobots via the Assembly of In Situ Synthesized and Surfactant-Coated Magnetic Nanoparticles.

This study showcases the possibility of tailoring the wettability of magnetic bacterial cellulose (m-BC) composites by the combined effect of in situ synthesized magnetic nanoparticles (MNPs) distribution and simultaneous oleic acid (OA) coating within the BC matrix. This combined effect of MNPs and OA resulted in m-BC composites exhibiting solvent-dependent and time-dependent surface-wetting behavior, which was not observed in either individual cases of BC that have been modified with OA or BC that has MNPs adsorbed on its fibers. This tailored wettability in m-BCs was achieved via varying the concentrations of iron precursors, which governed the arrangement and morphology of MNPs (uniformly or clustered) on the BC membrane, although the same fraction of MNPs was observed in both the m-BCs. Finally, we have achieved delayed water absorption in m-BC_x (synthesized in a comparatively lower precursor concentration) and no absorption of water in m-BC_4x (synthesized in a 4-times-higher precursor concentration). The m-BC_4x composite maintained its hydrophobic characteristics in diverse environments, ranging from highly acidic conditions (pH 1.2) to physiological environments at pH 4, 5.5, and 7.4. The MNP agglomerates on the BC nanofibers in the m-BC_4x composite were found to be instrumental in attaining a stable cyclic absorption performance with structural integrity. Additionally, the magnetic-inducing heat generation efficiency of the m-BCs can be extended for evaporating low-boiling-point solvents. The present study expands the frontiers of BC-based magnetic composites by emphasizing the assembly of surfactant-coated magnetic nanostructures in their responsiveness to polar/nonpolar liquids with stable performance even in complex scenarios.

Designing Bilayer Heterostructure Functional Polymer Electrolytes with Interfacial Engineering Strategy for High‐Performance Lithium Metal Batteries

AbstractThe uncontrollable lithium (Li) dendrites growth and complex electrode/electrolyte interface (EEI) problems are hindering the further application of high energy density lithium metal batteries (LMBs) in practice. Herein, a bilayer heterostructure gel polymer electrolyte (BGPE) is designed by directly curing functional boron‐containing monomers on the electrode surface to ensure excellent conductivity while solving the interface problems, achieving durable high voltage resistance and Li dendrites suppression. The unoccupied p‐orbital boron moiety of the 3D crosslinked network in BGPE not only improves the Li+ transference number (0.78), but also enhances the interfacial stability of the Li metal and inhibits the dendrites growth by anchoring PF6− anions and regulating the uniform Li deposition, thus ensuring a long cycle for Li/BGPE/Li cells. In addition, the functional additives tris(trimethylsilyl) phosphite and tris(pentafluorophenyl)borane can preferentially oxidize and decompose to form stable B, F, and Si‐rich EEIs, and effectively regulate the uniform growth of EEI. Thus, the LiNi0.5Co0.2Mn0.3O2/BGPE/Li and LiFePO4/BGPE/Li full cells exhibit stable cycling and excellent rate performance. This work provides a guiding design direction to address the EEI problems for high energy density LMBs.

Partial‐Oxidation Enabling Homologous Ru/RuO2 Heterostructures With Proper d‐Dand Center as Efficient and Durable Cathode Catalysts for Ultralong Cycle Life in Li–O2 Batteries

AbstractThe sluggish cycle kinetics is one of the major obstacles to the commercial application of Li–O2 batteries (LOBs), despite their large theoretical energy density. Efficient and long‐term durable cathode catalysts are urgently desired to strengthen their cycle stability and rate performance. Density functional theory calculations reveal that Ru/RuO2 Mott–Schottky heterostructures can manipulate the adsorption capacities of intermediates by modulating the d‐band center and redistribute interfacial charges, enabling efficient redox kinetics, reducing overpotentials, and optimizing the growth pathway of discharge products. Herein, a wet impregnation approach followed by partial oxidization of Ru nanodots to construct homologous Ru/RuO2 heterostructures as advanced cathode catalysts for boosting the electrochemical activities of LOBs is employed. They exhibit superior electrochemical performance, including high discharge specific capacity (17 120 mAh g−1 at 200 mA g−1), small overpotential (0.96 V), and ultralong cycle lifetime of 1209 cycles (>2400 h) at 500 mA g−1. Over 1260‐h stable cycle in air atmosphere at 500 mA g−1 demonstrates the potential application prospects of the Ru/RuO2 heterostructures in Li‐air batteries. Multiple ex/in situ measurements and theoretical calculation are conducted to investigate the optimizing mechanism of electrochemical performances.

High-Conductivity and Ultrastretchable Self-Healing Hydrogels for Flexible Zinc-Ion Batteries.

Aqueous zinc-ion batteries are promising candidates for flexible energy storage devices due to their safety, economic efficiency, and environmental friendliness. However, the uncontrollable dendrite growth and side reactions at the zinc anode hinder their commercial application. Herein, we designed and synthesized a dual network self-healing hydrogel electrolyte with zwitterionic groups (PAM-PAAS-QCS), which can be used for the large deformations of flexible devices due to its excellent stretchability (ε = 5100%). The incorporation of zwitterionic groups into the PAM-PAAS-QCS hydrogel electrolyte endows it with high ionic conductivity (33.61 mS/cm), a wide electrochemical stability window, and the ability to suppress zinc dendrite formation and side reactions. Besides, the Zn//Zn symmetric cell with PAM-PAAS-QCS can stably plate and strip zinc for 1500 h at 0.5 mA/cm2, and the Zn//Polyaniline full cell retains 82.4% of its capacity after 1500 cycles at 1 A/g. Additionally, flexible batteries based on both the original and self-healed PAM-PAAS-QCS hydrogel electrolytes demonstrate good cycling stability and stable charge-discharge performance under various bending conditions. This self-healing hydrogel electrolyte with excellent stretchability and high ionic conductivity is expected to pave the way for the development of high-performance flexible energy storage and wearable devices.

A Highly Stable and Non-Flammable Deep Eutectic Electrolyte for High-Performance Lithium Metal Batteries.

Deep eutectic electrolytes (DEEs) are regarded as one of the next-generation electrolytes to promote the development of lithium metal batteries (LMBs) due to their unparalleled advantages compared to both liquid electrolytes and solid electrolytes. However, its application in LMBs is limited by electrode interface compatibility. Here, we introduce a novel solid dimethylmalononitrile (DMMN)-based DEE induced by N coordination to dissociate LiTFSI. We confirmed that the DMMN molecule can promote the dissociation of LiTFSI by the interaction between the N atom and Li+, and form the hydrogen bond with TFSI- anion, which can promote the dissociation of LiTFSI to form DEE. More importantly, due to the absence of active α-hydrogen, DMMN exhibits greatly enhanced reduction stability with Li metal, resulting in favorable electrode/electrolyte interface compatibility. Polymer electrolytes based on this DEE exhibit high ionic conductivity (0.67 mS cm-1 at 25 °C), high oxidation voltage (5.0 V vs. Li+/Li), favorable interfacial stability, and nonflammability. Li‖LFP and Li‖NCM811 full batteries utilizing this DEE polymer electrolyte exhibit excellent long-term cycling stability and excellent rate performance at high rates. Therefore, the new DMMN-based DEE overcomes the limitations of traditional electrolytes in electrode interface compatibility and opens new possibilities for improving the performance of LMBs.

Highly Conductive Two-Dimensional FeTHBQ/Graphene Nanocomposite as the Cathode Material for Lithium-Ion Batteries.

Constructing high-performance coordination polymer (CP) cathodes for lithium-ion batteries based on the redox reactions of both high-potential transition metal ions and high-capacity organic ligands has attracted extensive attention. However, CP cathodes suffer from structural degradation, low electrical conductivity, and sluggish diffusion kinetics, resulting in poor cycling stability and inferior rate capability. Herein, the ultrafine FeTHBQ (THBQ = tetrahydroxy-1,4-benzoquinone) CP nanoparticles in situ grew on both sides of graphene nanosheets to form the uniform two-dimensional (2D) FeTHBQ/Graphene nanocomposite with a sandwich structure via a one-pot solvothermal method. The highly conductive graphene skeleton promotes the electronic conduction and structural stability for the 2D FeTHBQ/Graphene nanocomposite. Besides, compared with bulk FeTHBQ, the primary FeTHBQ nanoparticles in the FeTHBQ/Graphene nanocomposite have smaller particle sizes with larger specific surface areas. This not only shortens the Li+ diffusion distance in the FeTHBQ crystal but also benefits Li+ transfer between the electrolyte and the electrode. In the FeTHBQ/Graphene nanocomposite, the active material of FeTHBQ manifested multiple redox centers of transition metal ions (Fe3+/Fe2+) and carbonyls (C═O/C-O-) in THBQ ligands. Owing to the enhancements of structural stability, electronic conduction, and Li+ diffusion kinetics, the 2D FeTHBQ/Graphene nanocomposite presented a high lithium-ion storage capacity of 217.2 mA h g-1 at 50 mA g-1, a fast rate capability of 79.1 mA h g-1 at 5000 mA g-1, and a stable cycling performance of 87.2 mA h g-1 at 500 mA g-1 after 100 cycles. This work sheds light on the great opportunity for optimizing the electrochemical performances of CP-based functional electrode materials by combining with conductive substrates.

Experimental study on the cyclic performance of innovative self-centering three-dimensional isolation bearing

To improve vertical seismic isolation and seismic resilience in isolation bearings, this paper introduces an innovative three-dimensional isolation bearing combining a disc-spring system (DSS), a high-damping rubber bearing (HDR), and a horizontal spring system (HSS). The DSS is designed with low vertical stiffness to enhance vertical isolation, while the HSS provides self-centering force to improve the seismic resilience of the HDR. This study first presents a comprehensive theoretical analysis of the horizontal and vertical stiffness composition. The vertical performance of this three-dimensional isolation bearing is attributed to the DSS, while the HSS and HDR jointly contribute to its horizontal performance. Seven specimens were designed and subjected to shear-compression cyclic tests to assess the horizontal and vertical cyclic performance. Experimental parameters included loading amplitude, loading frequency, vertical pre-load, and DSS combinations for vertical tests, and axial compression force, loading frequency, shear strain, and HSS function in horizontal tests. The cyclic performance parameters for the three-dimensional isolation bearing, including equivalent damping ratio, equivalent stiffness, and energy dissipation, was evaluated. In general, the proposed three-dimensional isolation bearing exhibits stable cyclic performance and advantageous seismic resilience, warranting its promotion to practical engineering applications.

Medium and high temperature H2S removal via phosphazene polyoxometalate ionic liquids: Performance evaluation and mechanism exploration

The development of non-aqueous solvent desulfurizer is crucial to addressing the challenges associated with traditional liquid-phase wet desulfurization technologies. Based on this, we prepared a series of phosphazene polyoxometalate ionic liquids (PPILs) based of 1-butyl-3-methylimidazolium chloride using different kinds of phosphazenes (PNs) combined with polyoxometalate (POM), and used for hydrogen sulfide (H2S) dynamic absorption experiments. The effects of PN type and ratio, temperature and desulfurizer concentration on the desulfurization performance of different PPILs were explored. Among them, PPILs@IBuPN-9 as the optimal desulfurizer could keep almost 100 % desulfurization efficiency in the medium and high temperature range (100–200 °C). The results showed that the combination of PNs with POM significantly improved and widened the H2S removal performance and the operational temperature window of the desulfurizer. Besides, PPILs@IBuPN-9 required only air regeneration to maintain relatively stable cycle performance for at least four times and the sulfur capacity could be efficiently increased during multiple regenerations. It was found that the hydrogen bonding sites on IBuPN network formed significantly enhanced the H2S capture ability of PPILs and the sulfur capacity was substantially improved by S2− substitution of oxygen atoms in the POM according to the characterization results and density functional theory calculations. This study promotes the deep integration of polyoxometalate chemistry with ionic liquids in the field of gas purification and promotes the development of non-aqueous phase desulfurization process.

Calix[4]arene-decorated polymers of intrinsic microporosity for lithium isotopes separation

Due to the importance of lithium isotopes in the nuclear energy industry, there are increasing number of researchs on the lithium isotopes separation in recent years. However, the adsorbents used for lithium isotopes separation suffer from the low adsorption capacity and isotopes separation factor in aqueous phase, and is difficult to meet the requirements for industrial lithium isotopes production. In this work, two types of calix[4]arenes with different rim groups were incorporated into the polymer backbone. Both calix[4]arene decorated PIMs exhibited good lithium adsorption capacities in aqueous phase. Among them, 4-tert-butyl-calix[4]arene decorated PIM showed excellent lithium isotopes separation performance with a maximum lithium adsorption capacity of 67.99 mg·g−1 and an isotopes separation factor of 1.034 ± 0.003 in aqueous phase. The ease of preparing and stable cycling performance makes it potentially useful for industrial lithium isotopes production.

Transparent Photochromic Coatings for Smart Windows and Information Storage

AbstractOrganic–inorganic composite photochromic coatings receive significant attention in energy utilization and conservation due to their easy application and rapid photoresponse. However, their high sensitivity to moisture limits practical applications. This study fabricates organic–inorganic composite functional coatings using a simple one‐pot method, producing materials with excellent photoresponsive, water resistance, and thermal insulation. Unmodified phosphotungstic acid serves as the inorganic photochromic filler, while methacrylate derivatives act as the polymer matrix, resulting in coatings with high initial transparency (over 85%). After 5 min of UV exposure, the samples shift to nearly non‐transmittable states in the visible range and maintain color depth through 14 coloring‐erasing cycles. Unlike polyvinylpyrrolidone substrates, which absorb moisture and soften quickly, this coating has a static water contact angle of up to 91.7°, showing excellent water resistance. Additionally, the composite material provides effective heat insulation in simulated chamber experiments, lowering the temperature by 15 °C compared to untreated chambers. In summary, this composite coating, with its excellent thermal insulation, rapid light responsiveness, stable cycling performance, and outstanding waterproof capabilities, proves highly suitable for applications such as smart windows, information storage, and building energy efficiency.

Dextran Sulfate Sodium as Multifunctional Aqueous Binder Stabilizes Spinel LiMn2O4 for Lithium Ion Batteries

AbstractSpinel LiMn2O4 (LMO) has several beneficial properties for utilization as a cathode material for lithium‐ion batteries, including a high operating voltage, thermal stability, low cost, and eco‐friendliness. However, its application is limited by capacity fading due to structural transformation and manganese dissolution upon cycling. A method is proposed to resolve these two issues, using dextran sulfate sodium (DSS) as an aqueous binder to coat the LMO surface. DSS stabilizes the surface/interface structure of LMO by incorporating Na into the interstitial 16c sites, creating a uniform surface coating layer and promoting the formation of a homogeneous and stable cathode‐electrolyte interphase derived from the sulfate groups in DSS and enriched with LiF/LiSOxF. The aqueous DSS binder effectively suppresses the surface degradation and Mn dissolution of spinel LMO. The LMO electrode based on DSS exhibits superior cycling stability and rate performance compared with those of electrodes using the conventional poly(vinylidene difluoride) binder. These findings demonstrate the potential value of DSS as a multifunctional aqueous binder in stabilizing spinel LMO for lithium‐ion batteries.