Two-Dimensional Sulfonate-Functionalized Metal-Organic Framework Membranes for Efficient Lithium-Ion Sieving.

Two-dimensional (2D) membranes have shown promising potential for ion-selective separation but often suffer from the trade-off between permeability and selectivity. Herein, we report an ultrathin 2D sulfonate-functionalized metal-organic framework (MOF) membrane for efficient lithium-ion sieving. The narrow pores with angstrom precision in the MOF assist hydrated ions to partially remove the hydration shell, according to different hydration energies. The abundant sulfonate groups in the MOF channels serve as hopping sites for fast lithium-ion transport, contributing to a high Li-ion permeability. Then, the difference in affinity of the Li+, Na+, K+, and Mg2+ ions to the terminal sulfonate groups further enhances the Li-ion selectivity. The reported ultrathin MOF membrane overcomes the trade-off between permeability and selectivity and opens up a new avenue for highly permselective membranes.

Anion-Dominated Solvation in Low-Concentration Electrolytes Promotes Inorganic-Rich Interphase Formation in Lithium Metal Batteries.

While the formation of an inorganic-rich solid electrolyte interphase (SEI) plays a crucial role, the persistent challenge lies in the formation of an organic-rich SEI due to the high solvent ratio in low-concentration electrolytes (LCEs), which hinders the achievement of high-performance lithium metal batteries. Herein, by incorporating di-fluoroethylene carbonate (DFEC) as a non-solvating cosolvent, a solvation structure dominated by anions is introduced in the innovative LCE, leading to the creation of a durable and stable inorganic-rich SEI. Leveraging this electrolyte design, the Li||NCM83 cell demonstrates exceptional cycling stability, maintaining 82.85% of its capacity over 500 cycles at 1 C. Additionally, Li||NCM83 cell with a low N/P ratio (≈2.57) and reduced electrolyte volume (30 µL) retain 87.58% of its capacity after 150 cycles at 0.5 C. Direct molecular information is utilized to reveal a strong correlation between solvation structures and reduction sequences, proving the anion-dominate solvation structure can impedes the preferential reduction of solvents and constructs an inorganic-rich SEI. These findings shed light on the pivotal role of solvation structures in dictating SEI composition and battery performance, offering valuable insights for the design of advanced electrolytes for next-generation lithium metal batteries.

Crown Ether Electrolyte Induced Li2O2 Amorphization for Low Polarization and Long Lifespan Li-O2 Batteries.

Lithium-oxygen batteries possess an extremely high theoretical energy density, rendering them a prime candidate for next-generation secondary batteries. However, they still face multiple problems such as huge charge polarization and poor life, which lay a significant gap between laboratory research and commercial applications. In this work, we adopt 15-crown-5 ether (C15) as solvent to regulate the generation of discharge products in lithium-oxygen batteries. The coronal structure endows C15 with strong affinity to Li+, firmly stabilizes the intermediate LiO2 and discharge product Li2O2. Thus, the crystalline Li2O2 is amorphized into easily decomposable amorphous products. The lithium-oxygen batteries assembled with 0.5 M C15 electrolyte show an increased discharge capacity from 4.0 mAh cm-2 to 5.7 mAh cm-2 and a low charge overpotential of 0.88 V during the whole lifespan at 0.05 mA cm-2. The batteries with 1 M C15 electrolyte can cycle stably for 140 cycles. Furthermore, the amorphous characteristic of Li2O2 product is preserved when matched with redox mediators such as LiI, with the charge polarization further decreasing to 0.74 V over a cycle life of 190 cycles. This provides new possibilities for electrolyte design to promote Li2O2 amorphization and reduce charge overpotential in lithium-oxygen batteries.

Leakage behavior of toxic substances of naphthalene sulfonate-formaldehyde condensation from cement based materials.

Naphthalene sulfonate-formaldehyde condensatation (NSF) is the main component of the naphthalene based water reducers for cement based materials, as well as an organic substance with potential toxicity. However it is still uncertain whether it can leak from the cement based materials. In this work, the leakage ratio and adsorption behavior of NSF from various cement based materials such as the different water/cement (w/c) ratio, NSF content, types of cementitious materials as well as at different hydration time were evaluated. The product components of the cement based materials cured for different times were also quantified to explore the mechanisms which are responsible for the leakage and adsorption behaviors. The results indicate that more NSF, lower w/c ratio and less mineral admixture decrease the NSF leakage ratio. The leakage ratio of NSF from cement paste mixed 0.3% NSF is up to 50.8% at 0.5 h, and it decreases to 31.0% at 28 d. The leakage ratio of NSF from cement paste decreases as the hydration time prolongs. The lower leakage ratio corresponds to the higher adsorption capacity. Less adsorption capacity and thinner adsorption film imply that lower temperature and mineral admixture decrease the NSF adsorption behavior. When 0.3% NSF is added into the cement paste, the adsorption amount and NSF layer thickness are 5.53 mg/g and 0.98 nm, 5.87 mg/g and 4.7  nm at 0.5 h and 28 d respectively. The result demonstrates that the adsorption behavior of NSF in cement significantly increases at the initial several hours and gradually stabilizes after the first day. The X-ray powder diffractometer (XRD) results show that the contents of tricalcium silicate (C3S) and dicalcium silicate (C2S) continuously decline and the amorphous phases and ettringite (AFt) increase rapidly in the early stage. NSF adsorption and leakage behaviors are closely related to the hydration process of cement. These results indicate that NSF can definitely leak from the cement based materials and thus the NSF potential environmental pollution cannot be ignored. At least, it should be restricted or cautious to produce the water tower and pipe concrete structure with it. These results will sever as a theoretically reference for the pollution control as well as better application of NSF in cement-based materials.

Local Lattice Distortion Activate Metastable Metal Sulfide as Catalyst with Stable Full Discharge-Charge Capability for Li-O2 Batteries.

The direct lattice strain, either distortion, compressive, or tensile, can efficiently alter the intrinsic electrocatalytic property of the catalysts. In this work, we report a novel and effective strategy to distort the lattice structure by constructing a metastable MoSSe solid solution and thus, tune its catalytic activity for the Li-O2 batteries. The lattice distortion structure with inequivalent interplanar spacing between the same crystals plane were directly observed in individual MoSSe nanosheets with transmission electron microscopy and aberration-corrected transmission electron microscopy. In addition, in situ transmission electron microscopy analysis revealed the fast Li+ diffusion across the whole metastable structure. As expected, when evaluated as oxygen electrode for deep-cycle Li-O2 batteries, the metastable MoSSe solid solution deliver a high specific capacity of ∼730 mA h g-1 with stable discharge-charge overpotentials (0.17/0.49 V) over 30 cycles.

Synthesis of α-MnO2 nanowires modified by Co3O4 nanoparticles as a high-performance catalyst for rechargeable Li-O2 batteries.

The α-MnO2 nanowires uniformly coated with Co3O4 nanoparticles were prepared as a bi-functional catalyst for rechargeable Li-O2 batteries. The α-MnO2 nanowires were 5-20 nm in diameter, ranging between 5 and 10 µm in length. And the coated Co3O4 nanoparticles were around 5 nm in diameter. The α-MnO2/Co3O4 hybrid had a high specific surface area of 329.5 cm(2) g(-1), and showed excellent catalytic property. Both of the charge and discharge overpotentials are effectively reduced and the batteries could stably work for more than 60 cycles. It is demonstrated that the catalytic performance of the α-MnO2/Co3O4 hybrid is not only associated with the morphology and size of the catalyst, but also with their synergetic effects and the oxygen vacancies produced at the surface of MnO2. The results of charge-discharge cycling tests demonstrate that this α-MnO2/Co3O4 hybrid catalyst is a promising candidate for the Li-O2 batteries.

High-performance lithium storage in an ultrafine manganese fluoride nanorod anode with enhanced electrochemical activation based on conversion reaction.

A facile, one-step solvothermal reaction route for the preparation of manganese fluoride nanorods is successfully developed using manganese(II) chloride tetrahydrate (MnCl2·4H2O) as the manganese source and the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BmimBF4) as the fluorine source. X-ray diffraction, field-emission scanning electron microscopy and high-resolution transmission electron microscopy (HRTEM) are conducted to characterize the structural and microstructural properties of the synthesized MnF2. The pure-phase tetragonal MnF2 displays nanorod-like morphology with a diameter of about 20 nm and a length of several hundreds of nanometers. The electrochemical performance of the MnF2 nanorod anode for rechargeable lithium batteries is investigated. A reversible discharge capacity as high as 443 mA h g(-1) at 0.1 C is obtained for the lithium uptake reaction with an initial discharge plateau around 0.7 V. The striking enhancement in electrochemical Li storage performance in ultrafine MnF2 nanorods can be attributed to the small diameters of the nanorods and efficient one-dimensional electron transport pathways. Long cycle performance for 2000 cycles at 10 C with a stabilized capacity of about 430 mA h g(-1) after activation is also achieved. Furthermore, lithiated and delithiated MnF2 anodes are analyzed with HRTEM to elucidate the conversion mechanism for the electrochemical reaction of MnF2 nanorods with Li at a microscopic level.

Suppressing the dissolution of polysulfides with cosolvent fluorinated diether towards high-performance lithium sulfur batteries.

The dissolution and shuttle of polysulfides in electrolytes cause severe anode corrosion, low coulombic efficiency, and a rapid fading of the capacity of lithium-sulfur batteries. Fluorinated diether (FDE) was selected as a cosolvent in traditional ether electrolytes to suppress the dissolution of polysulfides. The modified electrolytes lead to a negligible solubility of polysulfides, as well as decreased corrosion of the lithium anode. In an optimal system, the cells show improved cycling performance with an average coulombic efficiency of above 99% and a highly stable reversible discharge capacity of 701 mA h g-1 after 200 cycles at a 0.5C rate. A combination of electrochemical studies and X-ray photoelectron spectroscopy demonstrates the sulfur reduction mechanism with three voltage plateaus.

Surface Acidity as Descriptor of Catalytic Activity for Oxygen Evolution Reaction in Li-O2 Battery.

Unraveling the descriptor of catalytic activity, which is related to physical properties of catalysts, is a major objective of catalysis research. In the present study, the first-principles calculations based on interfacial model were performed to study the oxygen evolution reaction mechanism of Li2O2 supported on active surfaces of transition-metal compounds (TMC: oxides, carbides, and nitrides). Our studies indicate that the O2 evolution and Li(+) desorption energies show linear and volcano relationships with surface acidity of catalysts, respectively. Therefore, the charging voltage and desorption energies of Li(+) and O2 over TMC could correlate with their corresponding surface acidity. It is found that certain materials with an appropriate surface acidity can achieve the high catalytic activity in reducing charging voltage and activation barrier of rate-determinant step. According to this correlation, CoO should have as active catalysis as Co3O4 in reducing charging overpotential, which is further confirmed by our comparative experimental studies. Co3O4, Mo2C, TiC, and TiN are predicted to have a relatively high catalytic activity, which is consistent with the previous experiments. The present study enables the rational design of catalysts with greater activity for charging reactions of Li-O2 battery.

The doping effect on the catalytic activity of graphene for oxygen evolution reaction in a lithium-air battery: a first-principles study.

A lithium-air battery as an energy storage technology can be used in electric vehicles due to its large energy density. However, its poor rate capability, low power density and large overpotential problems limit its practical usage. In this paper, the first-principles thermodynamic calculations were performed to study the catalytic activity of X-doped graphene (X = B, N, Al, Si, and P) materials as potential cathodes to enhance charge reactions in a lithium-air battery. Among these materials, P-doped graphene exhibits the highest catalytic activity in reducing the charge voltage by 0.25 V, while B-doped graphene has the highest catalytic activity in decreasing the oxygen evolution barrier by 0.12 eV. By combining these two catalytic effects, B,P-codoped graphene was demonstrated to have an enhanced catalytic activity in reducing the O2 evolution barrier by 0.70 eV and the charge voltage by 0.13 V. B-doped graphene interacts with Li2O2 by Li-sited adsorption in which the electron-withdrawing center can enhance charge transfer from Li2O2 to the substrate, facilitating reduction of O2 evolution barrier. In contrast, X-doped graphene (X = N, Al, Si, and P) prefers O-sited adsorption toward Li2O2, forming a X-O2(2-)···Li(+) interface structure between X-O2(2-) and the rich Li(+) layer. The active structure of X-O2(2-) can weaken the surrounding Li-O2 bonds and significantly reduce Li(+) desorption energy at the interface. Our investigation is helpful in developing a novel catalyst to enhance oxygen evolution reaction (OER) in Li-air batteries.

Hierarchical mesoporous iron-based fluoride with partially hollow structure: facile preparation and high performance as cathode material for rechargeable lithium ion batteries.

Hierarchical mesoporous structured iron based fluorides (abbreviated as HMIFs) are successfully synthesized for the first time by a solvothermal method through self-assembly. The fluorides are built from a large amount of nanorods with a size more than a dozen nanometers and exhibit dual phases consisting of Fe1.9F4.75·0.95H2O and FeF3·H2O. A possible formation mechanism is proposed by systematically investigating the synthesis conditions including temperature, reaction time and the amount of the fluorides source. The electrochemical performance of HMIFs as cathodes for rechargeable lithium batteries is investigated. A large reversible capacity exceeding 200 mA h g(-1) without any conducting agent coating and excellent cyclic performance with a residual capacity of 148 mA h g(-1) after 100 cycles are obtained at 0.1 C. In addition, an outstanding rate performance exceeding 100 mA h g(-1) at 5 C highlights the advantages of HMIFs materials for energy storage applications in high-performance LIBs.

A shuttle effect free lithium sulfur battery based on a hybrid electrolyte.

A room temperature hybrid electrolyte based lithium-sulfur cell was successfully cycled with an excellent coulombic efficiency of 100%. The initial discharge specific capacities of up to 1528 mA h g(-1), 1386 mA h g(-1) and 1341 mA h g(-1), respectively, at C/20, C/5 and C/2 rates were realized and remained at 720 mA h g(-1) after 40 cycles at the C/5 rate.

A Gel Polymer Electrolyte with High Uniform Na+ Flux and its Constructed Hybrid Interface Synergistically to Facilitate High-Performance Sodium Batteries.

Sodium metal batteries (SMBs) can be developed on a large scale to achieve low-cost and high-capacity energy storage systems. Gel polymer electrolyte (GPE) can relieve volatilization of liquid electrolyte, adapt to volume changes in electrodes, and better satisfy the requirements of long-term SMBs. Herein, a dense polyurethane-based GPE modified with polyacrylonitrile is synthesized by rapidly swelling two-component polyurethane/polyacrylonitrile electrospun fiber film. Compared to traditional porous GPEs obtained by swelling porous matrixes, the fiber film provides uniform high Na+ flux inside GPE due to its partial solubility property and ability to dissociate salts. Therefore, it can reduce the polarization effect and induce uniform metal deposition under high current in conjunction with its constructed hybrid N/F-containing solid electrolyte interface (SEI) that possesses low ionic diffusion barrier. The study demonstrates that GPE has an ionic conductivity of 1.816 mS cm-1 at 20 °C and an ion transference number of 0.53. The full battery (NVP/GPE/Na) assembled with this GPE and Na3V2(PO4)3 (NVP) cathode shows 90.8% capacity retention rate after 1000 cycles at 10 C. Considering the convenient preparation and outstanding electrochemical performances of the obtained GPE, it can also be matched with other electrodes in the future to expand the application of sodium-based batteries.

Effect of NiO Addition on the Sintering and Electrochemical Properties of BaCe0.55Zr0.35Y0.1O3-δ Proton-Conducting Ceramic Electrolyte.

Proton ceramic fuel cells offer numerous advantages compared with conventional fuel cells. However, the practical implementation of these cells is hindered by the poor sintering activity of the electrolyte. Despite extensive research efforts to improve the sintering activity of BCZY, the systematic exploration of the utilization of NiO as a sintering additive remains insufficient. In this study, we developed a novel BaCe0.55Zr0.35Y0.1O3-δ (BCZY) electrolyte and systematically investigated the impact of adding different amounts of NiO on the sintering activity and electrochemical performance of BCZY. XRD results demonstrate that pure-phase BCZY can be obtained by sintering the material synthesized via solid-state reaction at 1400 °C for 10 h. SEM analysis revealed that the addition of NiO has positive effects on the densification and grain growth of BCZY, while significantly reducing the sintering temperature required for densification. Nearly fully densified BCZY ceramics can be obtained by adding 0.5 wt.% NiO and annealing at 1350 °C for 5 h. The addition of NiO exhibits positive effects on the densification and grain growth of BCZY, significantly reducing the sintering temperature required for densification. An anode-supported full cell using BCZY with 0.5 wt.% NiO as the electrolyte reveals a maximum power density of 690 mW cm-2 and an ohmic resistance of 0.189 Ω cm2 at 650 °C. Within 100 h of long-term testing, the recorded current density remained relatively stable, demonstrating excellent electrochemical performance.

Interface Ionic/Electronic Redistribution Driven by Conversion-Alloy Reaction for High-Performance Solid-State Sodium Batteries.

NASICON-type Na+ conductors show a great potential to realize high performance and safety for solid-state sodium metal batteries (SSSMBs) owing to their superior ionic conductivity, high chemical stability, and low cost. However, the interfacial incompatibility and sodium dendrite hazards still hinder its applications. Herein, a conversion-alloy reaction-induced interface ionic/electronic redistribution strategy, constructing a gradient sodiophilic and electron-blocking interphase consisting of sodium-tin (Na-Sn) alloy and sodium fluoride (NaF) between NASICON ceramic electrolyte and Na anode is proposed. The NaxSny alloy-rich layer near the side of the sodium electrode acts as a superior conductor to enhance the anodic sodium-ion transport dynamics while the NaF-rich layer near the side of the ceramic electrolyte serves as an electron insulator to confine the interfacial electron turning ability, achieving uniform and dendrite-free Na deposition during the cycling. Profiting from the synergistic effect of the gradient interphase, the critical current density (CCD) of the assembled Na symmetric cell is significantly increased to 1.7 mA cm-2 and the cycling stability of that is as high as 1200 h at 0.5 mA cm-2. Moreover, quasi-solid-state sodium batteries with both Na3V2(PO4)3 and NaNi1/3Fe1/3Mn1/3O2 cathode display outstanding electrochemical performance.

Promoted Stability and Reaction Kinetics in Ni-Rich Cathodes via Mechanical Fusing Multifunctional LiZr2(PO4)3 Nanocrystals for High Mass Loading All-Solid-State Lithium Batteries.

Sulfide all-solid-state lithium battery (ASSLB) with nickel-rich layered oxide as the cathode is promising for next-generation energy storage system. However, the Li+ transport dynamic and stability in ASSLB are hindered by the structural mismatches and the instabilities especially at the oxide cathode/sulfide solid electrolyte (SE) interface. In this work, we have demonstrated a simple and highly effective solid-state mechanofusion method (1500 rpm for 10 min) to combine lithium conductive NASICON-type LiZr2(PO4)3 nanocrystals (∼20 nm) uniformly and compactly onto the surface of the single crystallized LiNi0.8Co0.1Mn0.1O2, which can also attractively achieve Zr4+ doping in NCM811 and oxygen vacancies in the LZPO coating without solvent and annealing. Benefiting from the alleviated interface mismatches, sufficient Li+ ion flux through the LZPO coating, promoted structural stabilities for both NCM811 and sulfide SE, strong electronic coupling effect between the LZPO and NCM811, and enlarged (003) d-spacing with enriched Li+ migration channels in NCM811, the obtained LZPO-NCM811 exhibits superior stability (185 mAh/g at 0.1C for 200 cycles) and rate performance (105 mAh/g at 1C for 1300 cycles) with high mass loading of 27 mgNCM/cm2 in sulfide ASSLB. Even with a pronounced 54 mgNCM/cm2, LZPO-NCM811 manifests a high areal capacity of 9.85 mAh/cm2. The convenient and highly effective interface engineering strategy paves the way to large-scale production of various coated cathode materials with synergistic effects for high performance ASSLBs.

Electrolyte Design for Lithium-Ion Batteries for Extreme Temperature Applications.

With increasing energy storage demands across various applications, reliable batteries capable of performing in harsh environments, such as extreme temperatures, are crucial. However, current lithium-ion batteries (LIBs) exhibit limitations in both low and high-temperature performance, restricting their use in critical fields like defense, military, and aerospace. These challenges stem from the narrow operational temperature range and safety concerns of existing electrolyte systems. To enable LIBs to function effectively under extreme temperatures, the optimization and design of novel electrolytes are essential. Given the urgency for LIBs operating in extreme temperatures and the notable progress in this research field, a comprehensive and timely review is imperative. This article presents an overview of challenges associated with extreme temperature applications and strategies used to design electrolytes with enhanced performance. Additionally, the significance of understanding underlying electrolyte behavior mechanisms and the role of different electrolyte components in determining battery performance are emphasized. Last, future research directions and perspectives on electrolyte design for LIBs under extreme temperatures are discussed. Overall, this article offers valuable insights into the development of electrolytes for LIBs capable of reliable operation in extreme conditions.

Surface Gradient Ni-Rich Cathode for Li-Ion Batteries.

Nickel-rich layered oxide cathode material LiNixCoyMnzO2 (NCM) has emerged as a promising candidate for next-generation lithium-ion batteries (LIBs). These cathode materials possess high theoretical specific capacity, fast electron/ion transfer rate, and high output voltage. However, their potential is impeded by interface instability, irreversible phase transition, and the resultant significant capacity loss, limiting their practical application in LIBs. In this work, a simple and scalable approach is proposed to prepare gradient cathode material (M-NCM) with excellent structural stability and rate performance. Taking advantage of the strong coordination of Ni2+ with ammonia and the reduction reaction of KMnO4, the elemental compositions of the Ni-rich cathode are reasonably adjusted. The resulted gradient compositional design plays a crucial role in stabilizing the crystal structure, which effectively mitigates Li/Ni mixing and suppresses unwanted surficial parasitic reactions. As a result, the M-NCM cathode maintains 98.6% capacity after 200 cycles, and a rapid charging ability of 107.5 mAh g-1 at 15 C. Furthermore, a 1.2 Ah pouch cell configurated with graphite anode demonstrates a lifespan of over 500 cycles with only 8% capacity loss. This work provides a simple and scalable approach for the in situ construction of gradient cathode materials via cooperative coordination and deposition reactions.

Highly Stable Protonic Ceramic Electrolysis Cells Based on Air Electrodes with Finger-Like Pores Current Collection Layers Running in High-Steam-Content Air.

The steam content in the air electrode is one of the major factors determining the efficiency and stability of protonic ceramic electrolysis cells (PCECs). In this work, the La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) current collection layer (CCL) film with unique finger-like pores was successfully prepared by the phase-inversion tape-casting technique (PT), which promoted the gas diffusion inside the electrode and effectively improved the stability of the single cell in high-humidity air. A screen-printed LSCF-BaCe0.7Zr0.1Y0.1Yb0.1O3 catalytic active layer (CAL) was also applied to match the thermal expansion coefficient (TEC) values and improve the interface combination. The electrochemical impedance spectroscopy (EIS) and distribution of relaxation time (DRT) studies of the symmetric cells showed that when the film was used to match different CALs as an air electrode, the gas diffusion inside the electrode was no longer restricted by the increasing steam content in air. The single cell exhibited a high electrolysis current density of 1 A cm-2 (1.25 V) at 650 °C; furthermore, no performance degradation was observed in this high current density when electrolyzed in air with 40 and 60% humidity for more than 250 h. These results present a simplified and economical scheme to develop air electrodes with high stability in wet air with a high steam content.

Long-Lifespan Lithium Metal Batteries Enabled by a Hybrid Artificial Solid Electrolyte Interface Layer.

Lithium metal batteries based on metallic Li anodes have been recognized as competitive substitutes for current energy storage technologies due to their exceptional advantage in energy density. Nevertheless, their practical applications are greatly hindered by the safety concerns caused by lithium dendrites. Herein, we fabricate an artificial solid electrolyte interface (SEI) via a simple replacement reaction for the lithium anode (designated as LNA-Li) and demonstrate its effectiveness in suppressing the formation of lithium dendrites. The SEI is composed of LiF and nano-Ag. The former can facilitate the horizontal deposition of Li, while the latter can guide the uniform and dense lithium deposition. Benefiting from the synergetic effect of LiF and Ag, the LNA-Li anode exhibits excellent stability during long-term cycling. For example, the LNA-Li//LNA-Li symmetric cell can cycle stably for 1300 and 600 h at the current densities of 1 and 10 mA cm-2, respectively. Impressively, when matching with LiFePO4, the full cells can steadily cycle for 1000 times without obvious capacity attenuation. In addition, the modified LNA-Li anode coupled with the NCM cathode also exhibits good cycling performance.