Stable Discharge Research Articles

Impact of diffusion layer structure of air electrodes on their performance in neutral zinc/iron - air batteries

Neutral metal-air batteries are of promising practical significance due to their excellent safety, environmental friendliness and strong resistance to carbon dioxide. Among them, the electrochemical performance and stability of air cathode will become a crucial factor restricting the development of neutral metal-air batteries. Herein, gas diffusion layer of an air electrode was constructed by applying different carbon materials including acetylene black (AB), carbon nanotubes (CNT), graphite (GP), ball milled graphite (m-GP) and their mixture with different mass ratios. Corresponding air electrodes were fabricated based on the MnO2/C as the catalyst. For the air electrode AB2@CNT8, its gas diffusion layer was obtained by using the mixture of AB and CNT with a mass ratio of 2:8, and it reveals good oxygen reduction reaction (ORR) performance and high discharge stability when applied to neutral zinc/iron - air batteries. In the neutral chloride electrolyte system, the discharge life of the AB2@CNTCNT8 zinc-air battery reaches 381.39h and its specific discharge capacity is 765 mAh·gZn-1. For the neutral AB2@CNTCNT8 iron-air battery, its specific discharge capacity reaches 863 mAh·gFe-1, and it can last a long working time of over 1384h. In addition, the performance of the air electrode AB2@CNTCNT8 that undergone a long-term operation can be quickly restored by simple hot water treatment. Results indicate that the air electrode AB2@CNTCNT8 has good performance, high stability and durability in the neutral chloride system, and is expected to be a potential candidate for the air cathode of neutral zinc/iron - air batteries.

Positive corona discharge of rod‐plate electrodes in high‐speed airflow

AbstractThe characteristics of positive corona discharge of rod electrode in high‐speed airflow are studied in this paper. The experiments were carried out in a wind tunnel with a maximum flow speed of 100 m/s in a dark room. The discharge voltage and current were recorded and the corona patterns were captured by a digital single lens reflex (DSLR) camera during the experiment. A discharge transition in rod electrode from streamer corona to mixed streamer‐glow corona, and finally to stable glow discharge was observed with the voltage increased. The increase of airflow speed resulted in a decrease of each corona inception voltages. The streamers will be suppressed and shifted towards the upwind side, while the glow layer will be promoted and shifted towards the downwind side in low and upwind side in high voltages. The glow corona current and the voltage show a quadratic function and the higher the airflow speeds, the bigger the coefficient of square of voltage. The distributions of peaks, pulse widths and interval times of streamer pulses were analysed, showing good correspondence with the streamer images. The measurements were explained by combining particle transport and local air pressure distribution.

Study on the Performance of Aqueous Aluminum‐Ion Battery with Al[TFSI]3 Electrolyte

Aqueous aluminum‐ion batteries have higher energy density and lower cost than traditional rechargeable batteries. Electrolytes play a vital role in aqueous aluminum‐ion battery and are directly related to battery performance. However, ionic liquid electrolytes suitable for aluminum are expensive and have potential environmental problems. To improve the energy density and reduce the environmental impact, this study innovatively proposes a new aqueous electrolyte. In this article, a battery preparation and performance testing bench is built to prepare a new aqueous aluminum‐ion battery. A novel aqueous aluminum‐ion battery is proposed using α‐MnO2 as the positive electrode, eutectic mixture‐coated aluminum anode (UTAl) as the negative electrode, and aluminum bistrifluoromethanesulfonate (Al[TFSI]3) aqueous solution as the electrolyte. The electrochemical performance of the prepared aqueous aluminum‐ion battery is studied under multiple working conditions. The results show that the assembled UTAl/Al[TFSI]3/α‐MnO2 battery exhibits an ultrahigh first‐cycle specific energy of up to 420 mAh g−1 at room temperature and a current density of 50 mA g−1 for 5 mol L−1 Al[TFSI]3. The newly developed battery can achieve a capacity retention rate of 63.4%, a Coulombic efficiency of over 94%, and a stable charge and discharge voltage platform of 1.65 and 1.4 V.

INFLUENCE OF BOUNDARY CONDINIONS ON THE PLASMA POTENTIAL IN A HELICON DISCHARGE WITH PLANAR ANTENNA

In a helicon discharge excited by a flat inductive antenna, situated at the discharge chamber end, distributions of plasma parameters have been measured by a thermo-emissive probe. The aim of the work was to define an influence producing by the bias potential of the surface being processed on plasma parameters in discharge chambers with either the dielectric or with conducting side walls. It was found that in the dielectric chamber application of a positive voltage and taking electron current to the surface under treatment causes increasing the plasma potential because the opposite sine current can not flow to the insulating wall. In the metal chamber increase of positive voltage on the surface leads to the discharge instability and break off for considerable taking electrons away from the discharge volume.

Dynamic characteristics of pumped thermal-liquid air energy storage system: Modeling, analysis, and optimization

Pumped thermal-liquid air energy storage (PTLAES) is a novel energy storage technology that combines pumped thermal- and liquid air energy storage and eliminates the need for cold storage. However, existing studies on this system are all based on steady-state assumption, lacking dynamic analysis and optimization to better understand the system’s performance under cyclic operation. To fill this gap, the mainbody-linearized cyclic dynamic model of the PTLAES system with packed bed thermal energy storage (TES) was first developed. Then, the dynamic characteristics of the baseline system were investigated. Sensitivity analyses were carried out on TES parameters. Minimal values of levelized cost of storage (LCOS) were observed for all parameters in the range of interest. Subsequently, the TES circuit was optimized, and a triple improvement of efficiency and energy density enhancement, discharge stabilization, and cost reduction was achieved. The optimized system's round-trip efficiency and energy density increased from 61.7% to 63.1% and from 141.9 kWh/m³ to 159.2 kWh/m³, and the LCOS decreased from 163.2 $/MWh to 159.4 $/MWh. A power offset ratio lower than 3% was reached, which is the lowest value ever reported in the literature. This study provides reference for future design and operation of the PTLAES system.

Optimization Design and Experimental Study of Solid Particle Spreader for Unmanned Aerial Vehicle

This study designed and investigated a solid particle spreader, as well as parameter optimization and experimental for a groove wheel, to mitigate the problems of low uniformity and poor control accuracy of solid particulate material UAV spreading. The discrete element method was used to simulate and analyze the displacement range and stability of each grooved wheel at low speeds. Furthermore, orthogonal regression and response surface analyses were used to analyze the influence of each factor on the stability of the discharge rate and pulsation amplitude. The results showed that the helix angle, sharpness, and length of the groove significantly influenced the application performance, whereas the number of grooves had no significant influence. The groove shape was eccentric, the helix angle was 50°, the length was 35 mm, and the number of grooves was 7. Additionally, the bench test results showed that in the range of 10–60 rpm, the relative deviation of the discharging rate between the simulation and bench test is from 0.47% to 10.39%, and the average relative deviation is 3.93%. Between the groove wheel rotation speed and discharge rate, R2 was 0.991, and the adjustable range of the discharge amount was between 3.68 and 23.43 g/s. The minimum and maximum variation coefficients of the average discharge rate among individual applicators were 1.01% and 2.79%, respectively, whereas the standard deviations were 0.09 and 0.46 g/s, respectively. In conclusion, the discharge stability and adjustable range of the spreader using the optimized groove wheel satisfied the requirements for solid particulate material discharge.

Оценка влияния напряжения нулевой последовательности на показатели безопасности при однофазных замыканиях в низковольтных судовых электросетях

One of the trends in the development of marine technology is the constant increase in the degree of electrification of ships. This process is accompanied by an increase in the danger of ship electrical networks, determined primarily by the operation of electrical installations with single-phase insulation damage. The consequences of this mode largely depend on the phase capacity of the electrical network. Moreover, the influence of phase capacitance on the danger of single-phase short circuits is determined not only by its size, but also by the degree of asymmetry. It is proved that it is precisely the asymmetry of the phase capacitances that causes the formation of zero-sequence voltage in ship electrical networks. An analysis of the indicators of the main dangers of the electrical network was carried out, taking into account the influence of zero-sequence voltage on them. It is proved that in electrical networks with an isolated neutral, the response time of the protection to cut off single-phase contact currents must be selected taking into account the fact that on-board networks may have asymmetrical phase capacitances. A set of theoretical and experimental studies was carried out to assess the influence of zero-sequence voltage on quantitative indicators of the danger of a ship's electrical network. An experimental assessment of the influence of phase capacitance asymmetry on the stability of electrical discharges during single-phase faults in electrical networks with an isolated neutral was carried out. It has been demonstrated that during short circuits through an unstable electric discharge, the presence of a zero-sequence voltage leads to a significant increase in explosion and fire hazard indicators of the electrical network, such as power and energy released at the site of insulation damage. It was revealed that increased safety can be achieved by influencing the voltage on the neutral.

Electrochemical behavior and discharge performance of Al-1Zn-0.4Mn-0.1Sn-xBi as anode alloys for Al-air battery in KOH solution

Al-1Zn-0.4Mn-0.1Sn-xBi (x = 0, 0.5, 0.10, 0.15, 0.20) alloys are prepared as anode materials in alkaline Al-air batteries by adding alloying elements to low-cost commercial purity aluminum to investigate their electrochemical behavior and discharge performance. The results show that among the five alloys, Al-1Zn-0.4Mn-0.1Sn-0.15Bi alloy has the best comprehensive corrosion resistance and discharge performance in 4 M KOH electrolyte at room temperature. Specifically, Al-1Zn-0.4Mn-0.1Sn-0.15Bi has the most negative corrosion potential of −1.484 V and the smallest corrosion current density of 42.80 mA cm−2, which can be attributed to the largest protective film impedance. The hydrogen evolution rate of this alloy is as low as 0.244 ml cm−2 min−1. Upon discharge at a current density of 60 mA cm−2, this anode alloy achieves an anode efficiency of 89.20 % and a specific capacity of 2656 Ah kg−1. Furthermore, when the discharge current density is further increased to 90 mA cm−2, it can still maintain a stable discharge at a high cell voltage of 1.01 V, and the power density reaches 90.9 mW cm−2. Therefore, Al-1Zn-0.4Mn-0.1Sn-0.15Bi can be considered as a suitable anode alloy for high-power-density discharge in Al-air batteries.

Enhancing the Stability of Lithium Metal Batteries with the Polydopamine-Coated Insulating Scaffold

Lithium metal is the most promising candidate for a high-capacity anode material in Li-ion batteries owing to its high theoretical theoretical capacity (3,860 mAh g-1) and the lowest redox potential (-3.04 V vs S.H.E.).[1] Despite these advantages, the practical application of Li metal anodes (LMAs) is hindered by a number of significant challenges. For instance, LMAs tend to form non-uniform dendrite, continuous dead Li growth, and infinite volume expansion.[2] These issues result in short circuits and continuous consumption of the active material, consequently lowering the Coulombic efficiency (CE) and cycling stability of LMAs.Using a 3D scaffold in the anode is an effective method for to address the issue of infinite volume expansion. The porous structure of the 3D scaffold provides ample space to accommodate Li metal.[3] Among them, electrically insulating scaffolds that do not support electron transport not only promote bottom-up Li deposition behavior but also minimize side reactions between the electrolyte and the scaffold. However, a high current density can lead to the formation of dendritic Li, which can make it challenging to achieve uniform and dense lithium growth on the surface during repeated plating/stripping processes. Therefore, the use of an insulating scaffold requires the introduction of functionalized materials to suppress dendritic formation of Li metal.Furthermore, to achieve further improvements, some studies have investigated the incorporation of polar functional groups into the insulating 3D structure.[4] Notably, these polar functional groups possess the capability to establish strong interactions with Li ions, which can facilitate the uniform distribution of these ions and prevent dendrite formation.[5] In this study, we utilized polydopamine (PDA) which contains polar functional groups such as O-H and N-H2, on a 3D insulating scaffold. These polar functional groups promote increased ionic conductivity and uniform deposition of Li ions by interacting with Li ions through Columbic forces.[6] Consequently, we expected that the advantageous properties of PDA would enhance the charge transfer reaction rate and cycling stability of LMBs.In this study, we aimed to introduce the utilization of a 3D polytetrafluoroethylene (PTFE) scaffold coated with PDA to achieve highly stable and high-energy LMBs. The insulating nature of the PTFE scaffold is expected to facilitate the "bottom-up" formation of Li deposition, while the PDA coating attracts Li ions, enabling homogenization of the Li-ion distribution and uniform growth of Li (Figure 1a). This design aims to simultaneously achieve both high energy density and improved cyclic stability in LMB full cells using our 3D scaffold.To elucidate the enhanced performance of the Lithium Metal Batteries (LMBs) equipped with PDA-coated 3D PTFE scaffold (PD-3P), we conducted a comparative study, including bare Cu foil and the 3D PTFE scaffold (3P) as control groups. Specifically, when tested at a high current density of 1 C with a 3.2 mAh cm-2 NCM, the PD-3P scaffold-based full cell exhibited a stable discharge capacity (Figure 1b).

Cathode Performance of ZnMn₂O₄ for Zn Anode Rechargeable Batteries

Zinc anode rechargeable batteries (ZABs) are expecting a promising rechargeable battery for next-generation power systems due to a low cost, environmental compatibility, high safety, and high energy density of Zn anode. Although various cathode materials are currently being investigated, no cathode material with high discharge capacity, cycle stability, and high potential has been reported1 . At present, MnO2 is the most promising materials however, cycle stability is still not enough high. In this study, ZnMn2O4 which is the inactive phase of Zn-MnO2 battery using alkaline electrolyte, was focused as cathode using various acidic electrolyte. Optimization of dopant and also additives to electrolyte was studied.ZnMn2O4 was synthesized with spray pyrolysis method using nitrate solution of Zn and Mn. The cathode was prepared by mixing ZnMn2O4, acetylene black, and PTFE at 7:2:1 weight ratio and pressed onto Ti mesh. The cell consists of Zn anode, glass separator, and the ZnMn2O4 cathode prepared. Charge-discharge measurements were performed in constant current mode with three electrodes cell at current density of 0.2 mA/cm².The prepared ZnMn2O4 powder was a sphere shape and SEM observation suggest that inner of particles are vacant, microcapsule structure. Among the electrolytes examined, 3M Zn(OTf)₂+0.1M Mn(OTf)₂ and 3M ZnSO₄+0.1M MnSO₄ were found to be suitable from cycle stability and discharge capacity. In particular, Zn-ZnMn2O4 cell using 3 M Zn(OTf)₂+0.1M Mn(OTf)2 shows discharge capacity larger than 200mAh/g and more than 50 cycles of charge and discharge.Ex situ XRD showed that the MnO peak was appeared after discharge from 1.9 to 0.8V and it is disappeared to be ZnMn2O4 peaks after charge to 1.9V. Consequently, the charge and discharge of Zn-ZnMn2O4 cell is stored electricity by the redox reaction between Mn2+ and Mn3+. Considering the stable discharge capacity and high potential, Zn-ZnMn2O4 battery is highly interesting as rechargeable large capacity battery. Acknowledgement; This presentation is based on results obtained from a project, JPNP21006, commissioned by the New Energy and Industrial Technology Development Organization (NEDO), Japan.1) N. Zhang, X. Chen, M. Yu, Z. Niu, F. Cheng, J. Chen, Chem Soc Rev, 2020, 49, 4203. Figure 1

All-Solid-State Lithium–Sulfur Batteries Enabled By Single-Ion Conducting Particle Electrolytes

The demand for safer alternatives to liquid electrolytes in lithium-ion batteries has stimulated the development of all-solid-state lithium batteries. These advanced batteries aim to mitigate potential hazards associated with flammability and dendrite formation during operation. Additionally, the integration of solid-state electrolytes creates opportunities to improve the energy and power densities of lithium batteries by enabling the direct utilization of lithium metal as the anode. In this study, we designed solid-state hybrid electrolytes with single-ion conducting properties by co-assembling binary polymer nanoparticles with large surface areas and excellent thermodynamic compatibility. These electrolytes were developed by synthesizing two distinct types of core–shell polymer nanoparticles with mechanically robust cores and shells capable of facilitating Li+ transport. By controlling the nanoparticle size and number, we created superlattices that optimized the Li+ concentration and transport. The electrolytes exhibited a remarkable ionic conductivity (10-4 S cm-1), lithium transference number (0.94), electrochemical stability (up to 6 V), and modulus (0.12 GPa) at 25 °C. The mechanical strength of these electrolytes depended minimally on temperature at 25–150 °C because of the robustness of the cores. These results unequivocally establish the remarkable superiority of the BNPs electrolyte, which avoid the conventional trade-off between conductivity and mechanical strength through the unique design of superlattice structures, thereby representing a significant breakthrough in the field of solid-state single-ion electrolytes. When implemented in Li–S batteries with no liquids, they demonstrated a stable discharge capacity exceeding 1008 mAh g-1, a cycle life of over 200 cycles, and a rate capability with a discharge capacity of 627 mAh g-1 at 3C. Our findings will pave the way for the safe operation of future high-energy-density lithium batteries utilizing solid-state hybrid electrolytes. Figure 1

Discharge Performance of FeF3-Based Cathode for Thermal Battery

Thermal battery is used in military application, which can be stored for a long time in an inactive state, and activated by heat. The most commonly used cathode material for thermal battery is FeS2, known for its ease of manufacturing and stable discharge behavior due to low side reactions. However, it has the disadvantage in terms of the energy density as a result of the low discharge voltage. We researched the various cathode materials, and focused on FeF3, which has covalent bonds and thus has a theoretically high discharge voltage. But, the low electrical conductivity of covalent bonds necessitates the addition of a conductive material. It has been reported that CNT significantly improved the conductivity by forming a conductive network among FeF3 particles. In this research, we manufactured the FeF3-based cathode with CNT and salt by powder press molding. The unit cell was constructed with LiCl-LiBr-LiF(with MgO) electrolyte and Li-Si anode and its discharge performance was measured at 500 ℃. We applied a pulse current to the unit cell to compare the internal resistance of the cathode with varying CNT content. The open-circuit voltage of FeF3 was measured at 2.7 V which is higher than 1.9 V of FeS2 making it suitable as a high voltage cathode. But as shown in Figure 1, FeF3 had a higher internal resistance than that of FeS2 with a particularly rapid voltage drop at the begging of discharge. This phenomenon results from a complex effect of side reactions with salt and interfacial reaction with the electrolyte in addition to electrical conductivity. Increasing the CNT content improved this tendency, but it also led to deterioration in a mechanical strength caused by the spring back effect. We investigated the discharge performance of unit cells for the application of FeF3 as a future cathode for thermal battery. Figure 1

Hydrothermally Grown Dual-Phase Heterogeneous Electrocatalysts for Highly Efficient Rechargeable Metal-Air Batteries with Long-Term Stability

Metal-air batteries as alternatives to the existing lithium-ion battery are becoming increasingly attractive sources of power due to their high energy-cost competitiveness and inherent safety; however, their low oxygen evolution and reduction reaction (OER/ORR) performance and poor operational stability must be overcome prior to commercialization. Herein, it is demonstrated that a novel class of hydrothermally grown dual-phase heterogeneous electrocatalysts, in which silver-manganese (AgMn) heterometal nanoparticles are anchored on top of 2D nanosheet-like nickel vanadium oxide (NiV2O6), allows an enlarged surface area and efficient charge transfer/redistribution, resulting in a bifunctional OER/ORR superior to those of conventional Pt/C or RuO2. The dual-phase NiV2O6/AgMn catalysts on the air cathode of a zinc-air battery lead to a stable discharge–charge voltage gap of 0.83 V at 50 mA cm−2, with a specific capacity of 660 mAh g−1 and life cycle stabilities of more than 146 h at 10 mA cm−2 and 11 h at 50 mA cm−2. The proposed new class of dual-phase NiV2O6/AgMn catalysts are successfully applied as pouch-type zinc-air batteries with long-term stability over 33.9 h at 10 mA cm−2. Figure 1

Electrochemical Characteristics of Rechargeable MnO x /Zn Battery

The charge/discharge characteristics of several types of manganese oxides with different structures as positive electrodes for zinc negative electrode batteries were evaluated. It is said that MnOOH is formed in the discharge reaction of γ-MnO2, but when the charge/discharge reaction was performed using β-MnO2 as the positive electrode, the formation of Mn2O3 and Mn3O4 instead of MnOOH was observed in the first discharge reaction. After the second cycle, no reversible reformation of β-MnO2 due to charging was observed. Furthermore, due to the charge/discharge reaction, zinc was dissolved from the zinc negative electrode, and basic zinc compounds were observed as a by-product in both the positive and negative electrodes. After the second cycle, the amount of Mn2O3 and Mn3O4 produced increased and decreased each time the discharge and charge were repeated. The discharge capacity showed a stable discharge capacity of ca.200 Ahkg-1 until about 30 cycles, but after that it gradually decreased to 105 Ahkg-1 at 100 cycles.

Improving the Performance of Silicon-Based Negative Electrodes in All-Solid-State Batteries by In Situ Coating with Lithium Polyacrylate Polymers.

In all-solid-state batteries (ASSBs), silicon-based negative electrodes have the advantages of high theoretical specific capacity, low lithiation potential, and lower susceptibility to lithium dendrites. However, their significant volume variation presents persistent interfacial challenges. A promising solution lies in finding a material that combines ionic-electronic conductivity, stable physicochemical properties, and adhesive characteristics. Poly(acrylic acid) (PAA) is widely used in liquid-state batteries due to its superior properties compared to polyvinylidene fluoride (PVDF). In this study, silicon particles were coated with varying concentrations of PAA and LiPAA using an in situ liquid-phase coating method to form electrode sheets. The experimental and analytical results revealed significant trends in the impact of different additive concentrations on the electrochemical performance, with 1.0 wt % LiPAA showing notable improvements in Coulombic efficiency, rate capability, and long-term cycling stability. The assembled all-solid-state batteries exhibited a high initial discharge capacity of 3200 mAh/g, with a capacity retention of 81.9% after 300 cycles at 0.3 C, and a stable discharge capacity of 1300 mAh/g at a 2 C rate. A rapid and efficient in situ liquid-phase coating method for LiPAA was developed and confirmed through FTIR, XRD, and TEM characterization. SEM and XPS analyses demonstrated that LiPAA encapsulation effectively alleviates interfacial issues. This study demonstrated for the first time that an appropriate amount of LiPAA coating on silicon particles can mitigate the interfacial challenges caused by the volume expansion of silicon-based negative electrodes. These findings improve electrochemical performance and promote the application of silicon-based negative electrodes in all-solid-state batteries.

Glow-to-arc transition in graphite cathode with high-current magnetron discharge

The glow-to-arc transition is a critical phenomenon in plasma discharges, commonly leading to detrimental effects. The physical mechanisms triggering this transition remain poorly understood. The advent of a discharge called Hyper-Power Impulse Magnetron has opened possibilities. Hyper-Power Impulse Magnetron allows the glow mode to be maintained over long periods (1 ms) and at high-current densities (>5 A .cm−2), which has unveiled certain features in the glow-to-arc transition. This work focuses on a graphite target that transits easily in the arc regime. The high-speed video-camera analysis revealed specific properties of graphite in ExB discharges, and the statistical study of the arc transition revealed differences from other refractory target materials. The early stage of cathodic spot formation, observed as bright dots, will be presented and analyzed within the known “ecton” and “vaporization” models for spot formation. This experimental study highlights the role of luminous spot formation prior to arc transition, with possible optimization on the stability of magnetron discharges.

Tellurium Enriched Over‐Oxidized MoTe2 Anchored MXene Sheets: A Promising Li‐ion Battery Anode Material

AbstractTo address the challenge of low electronic and ionic conductivities in lithium‐ion batteries (LIBs), we synthesized MoTe2@Ti3C2Tx via a modified hydrothermal route. This 2D van der Waals composite exhibited a stable reversible specific discharge capacity of 566 mAh/g at 0.1 C (67 mA/g) and retained 71 % of its initial capacity during rate performance tests. Notably, cycling stability tests revealed an increased discharge capacity of 316.4 mAh/g after 564 cycles at 0.4 C (268 mA/g), which improved further to 378.2 mAh/g after 922 cycles at 1 C (670 mA/g). The exceptional electrochemical performance stems from the unique MoTe2@Ti3C2Tx architecture, enhancing Li+ site exposure and ensuring structural stability. This composite emerges as a promising and easily synthesizable advanced anode material for LIBs, offering enhanced conductivity and stability.

Single organic electrode for multi-system dual-ion symmetric batteries

The large void space of organic electrodes endows themselves with the capability to store different counter ions without size concern. In this work, a small-molecule organic bipolar electrode called diquinoxalino[2,3-a:2’,3’-c]phenazine-2,6,10-tris(phenoxazine) (DQPZ-3PXZ) is designed. Based on its robust solid structure by the π conjugation of diquinoxalino[2,3-a:2’,3’-c]phenazine (DQPZ) and phenoxazine (PXZ), DQPZ-3PXZ can indiscriminately and stably host 5 counter ions with different charge and size (Li+, Na+, K+, PF6− and FSI−). In Li/Na/K-based half cells, DQPZ-3PXZ can deliver the peak discharge capacities of 257/243/253 mAh g−1cathode and peak energy densities of 609/530/572 Wh kg−1cathode, respectively. The Li/Na/K-based dual-ion symmetric batteries can be constructed, which can be activated through the 1st charge process and show the stable discharge capacities of 85/66/72 mAh g−1cathode and energy densities of 59/50/52 Wh kg−1total mass, all running for more than 15000 cycles with nearly 100% capacity retention.

A modified separator based on ternary mixed-oxide for stable lithium metal batteries

Li metal batteries (LMBs) are among the most promising options for next-generation secondary batteries under the rapidly growing demand for high-energy–density electrochemical energy storage. However, the implementation of LMBs are hindered by major obstacles such as dentritic Li deposition and low cycling Coulombic efficiency. A practical functional separator is developed in this study, which consists of a Lewis acidic mixed oxide of ZrO2-SiO2-Al2O3 as a functional coating with anion anchoring ability to modulate ion transport in the vicinity of the Li metal anode, delivering a high Li+ transference number of 0.88 in carbonate electrolytes that suppresses dendrite formation. The strong Lewis acid sites in ZrO2-SiO2-Al2O3 originate from coordinatively unsaturated Zr4+ ions, which immobilize anions and reduce their decomposition rate. This significantly improves the chemical stability of the electrolyte and induces a more stable solid electrolyte interphase layer. The modified separator enables an anode-free cell containing a high-loading LiNi0.8Co0.1Mn0.1O2 cathode to present stable charge and discharge cycling for 150 cycles at 0.5C. By effectively suppressing Li dendrite growth and supporting the long-term operation of anode-free LMBs, this study offers a novel approach to rationally design mixed oxides with high Lewis acidity for functional separators.

Regulating the Helmholtz plane by trace ionic liquid additive for advanced Al-air battery

Al-air batteries (AABs) are the next generation of alternative energy sources due to their high theoretical energy density, low cost, and environmental friendliness. Researchers have been interested in AABs with stable discharge in alkaline solution, long discharge time, and high conductivity. However, the uncontrolled self-corrosion of the Al anode and the severe hydrogen evolution reaction in alkaline electrolytes have been two major drawbacks hindering the commercial development of AABs. These shortcomings reduce the Al anode's utilization and significantly shorten the battery's service life. Herein, the Helmholtz plane structure was reconstructed using an ionic liquid additive called 1-aminopropyl-3-methylimidazolium bromide (AMIB) to regulate the electrochemical interface between the electrolyte and the Al anode. Electrochemical tests found that when 3 mM AMIB was added, the corrosion inhibition efficiency could reach up to 60 %. Further surface analysis and theoretical calculations showed that AMIB can form a dense and uniform protective layer on the surface of the Al anode substrate, which reduces the anode corrosion, lowers the active centers for hydrogen evolution on the Al surface, and reduces the hydrogen evolution rate. The full-cell studies found that the specific capacity of the cell increased from 1227 to 2564 mAh g−1, the energy density increased from 1546 to 3359 Wh kg−1, and the Al anode utilization increased from 41.2 % to 86.1 % as the AMIB addition to the alkaline electrolyte risen from 0 to 3 mM. This method of electrolyte regulation provides an efficient strategy for the commercial development of AABs.