Discharge Platform Research Articles

High-Performance Aqueous Sodium-Ion Battery Based on Graphene-Doped Na2MnFe(CN)6–Zinc with a Highly Stable Discharge Platform and Wide Electrochemical Stability

High-Performance Aqueous Sodium-Ion Battery Based on Graphene-Doped Na₂MnFe(CN)₆–Zinc with a Highly Stable Discharge Platform and Wide Electrochemical Stability

High utilization rate thermal batteries using PbCl2 as a cathode material

In view of the shortcomings of low utilization rate of disulfide cathode for thermal battery, chloride has been developed as a candidate material for thermal battery cathode. In this case, PbCl2 was tried to be used as a cathode material for thermal batteries and tested the electrical properties of single battery. The discharge specific capacity can reach 168 mAh/g at 450 °C and 0.5 C current, the voltage plateau reaches 1.8 V, and the active material utilization rate is as high as 87.5% when the cut-off voltage is 0.5 V. The only discharge platform and high utilization rate enable PbCl2 to be used as the active material for thermal batteries, which also provides a new direction for the chloride cathode active material for thermal batteries.

Nitrogen-doped carbon nanosheet coated multilayer graphite as stabilized anode material of potassium-ion batteries with high performances

By designing a multi-functional layer on the graphite surface, nitrogen-doped carbon nanosheet (NC) coated multilayer graphite (NC@MG) is synthesized as a promising anode material of potassium ion batteries (KIBs) with enhanced performances. Compared with the conventional graphite and multilayer graphite (MG), NC@MG exhibits a comparative flat discharge platform voltage of graphite anode and enhanced cyclic stability, rate performance, and specific capacity. It is indicated that the modified NC coating facilitates the formation of a stable SEI film on the NC@MG surface, which not only helps to improve the cycle stability, but also maximizes the embedding of K+ into the MG. The nitrogen elements in the NC also increase the electronic conductivity, which is beneficial to the rate performances of NC@MG. After 200 cycles at a current density of 50 mA g−1, the specific capacity of NC@MG is 252.7 mAh g−1; after 1000 cycles at 200 mA g−1, the specific capacity is still 215.7 mAh g−1. This work can not only obtain a stabilized graphite-based anode material of KIBs with enhanced electrochemical performances to date, but also provide a routine to modify and utilize the commercial graphite materials for KIBs.

Favorable Electrochemical Performance of LiMn2O4/LiFePO4 Composite Electrodes Attributed to Composite Solid Electrolytes for All-Solid-State Lithium Batteries.

Li1.5Al0.5Ge1.5(PO4)3 (LAGP)-PEO composite electrolytes are unstable in LiMn2O4. In addition, the discharge platform potential (2.8 and 4.0 V) difference of LiMn2O4 is relatively large, whereas the discharge platform potential (3.5 V) of LiFePO4 is between 2.8 and 4.0 V. Thus, LiMn2O4 and LiFePO4 can be compounded together to reduce the material platform voltage difference and obtain the advantages of both materials at the same time. Here, LiMn2O4/LiFePO4 composite cathodes were applied in solid-state batteries. LAGP-PEO(LiTFSI) was used as the electrolyte. The Li/composite cathode battery using composite electrolytes has a reversible capacity of 192.8 mAh g-1 at 50 °C and 0.1 C. It possesses favorable rate performance and exhibits very good cycling stability. In addition, the composite electrolytes can prevent the further occurrence of the Jahn-Teller effect. Meanwhile, the charge-transfer resistance slightly decreases in 10 cycles. The excellent capacity retention of the battery is connected with the excellent electrochemical stability and the well-interfaced contacts of the composite electrolytes with electrodes.

High-voltage and long-lasting aqueous chlorine-ion battery by virtue of "water-in-salt" electrolyte.

SummaryChloride-ion battery (CIB) is regarded as a promising electrochemical storage device due to their high theoretical volumetric capacities, low cost, and high abundance. However, low-cycle life limits its application in the energy storage field. Herein, we report a rechargeable CIB composed of a “water-in-salt” electrolyte, a zinc anode, and a carbon cathode (graphene, carbon nanotubes, carbon black). These cathodes exhibit initial reversible specific capacities of 136, 108, and 102 mAh g−1, respectively. Especially, a reversible discharge capacity of 95 mAh g−1 was retained after 2000 cycles when graphene is used as the cathode. Such high cycling stability was first reported in CIBs. Furthermore, the use of “water-in-salt” electrolytes has improved the discharge platform of aqueous CIBs to 2.6V. The charge and discharge mechanism of the carbon cathode was investigated by TEM, FTIR, Raman, and XPS, proving the chloride ions reversible absorption/desorption in carbon cathodes.

Spherical Li4Ti5O12/NiO Composite With Enhanced Capacity and Rate Performance as Anode Material for Lithium-Ion Batteries.

Compositing with metal oxides is proved to be an efficient strategy to improve electrochemical performance of anode material Li4Ti5O12 for lithium-ion batteries. Herein, spherical Li4Ti5O12/NiO composite powders have been successfully prepared via a spray drying method. X-ray diffraction and high-resolution transmission electron microscopy results demonstrate that crystal structure of the powders is spinel. Scanning electron microscopy results show that NiO uniformly distributes throughout Li4Ti5O12 matrix. It is found that compositing with NiO increases both discharge platform capacity and rate stability of Li4Ti5O12. The as-prepared Li4Ti5O12/NiO (5%) exhibits a high initial discharge capacity of 381.3 mAh g−1 at 0.1 C, and a discharge capacity of 194.7 mAh g−1 at an ultrahigh rate of 20 C.

A design of Nafion-coated bilayered quasi-solid electrolyte for lithium-O2 batteries with high performance

In this paper, a novel bilayer-structured quasi-solid polymer electrolyte (NSPE) has been designed with separate catholyte and anolyte, which compose of P(VDF-HFP)/Li-Nafion solid polymer electrolyte and TEMPO as cathodic additives. The SEM images shows that the surface morphology of NSPE is smoother and more uniform than that of SPE. The Li-O2 battery using NSPE showed high ionic conductivity, low interface impedance, good rate performance, and higher security and good cycling stability while reducing polarization. Lithium-air (also known as lithium-oxygen) batteries have attracted considerable global attention in recent years due to their extremely high energy density (11,140 W·h·kg −1 ). The electrolyte is a key element in lithium-air batteries and the traditional organic electrolyte has great safety risk due to leakage. On the contrary, the polymer electrolyte has the advantages of high safety, high stability and easy processing comparing with the organic liquid electrolytes. In this paper, a new idea was proposed to coat the Nafion membrane on a layer of polymer for blocking the oxidation reduction electric (RM) and Li based on the selective permeability on lithium ion of the Nafion membrane. Self-made thickness-controllable Nafion membrane, polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP) and 2,2,6,6-tetramethylpiperidinooxy (TEMPO) were used to prepare a quasi solid polymer electrolyte (NSPE). Electrochemical workstation and LAND battery testing system were used to perform a galvanostatic charge/discharge test on Li-O 2 . The ionic conductivity of NSPE was 4.3 × 10 −4 S·cm −1 at room temperature and the discharge platform was 2.6 V and the charging voltage was 3.7 V after 50 cycles with the cut-off capacity of 500 mA·h·g −1 .

Preparation of hierarchical LiNixCoyMnzO2 from solvothermal [NixCoyMnz](OH)2 via regulating the ratio of Ni, Co, and Mn and its excellent properties for lithium‐ion battery cathode

AbstractThe ternary‐layered oxide (LiNixCoyMnzO2) has become the most promising cathode material for lithium‐ion batteries due to the advantages of higher discharge platform, better conductivity, and higher theoretical capacity. The [NixCoyMnz](OH)2 with different ratios of nickel, cobalt, and manganese (NCM) was prepared by solvothermal method, and then ternary cathode material LiNixCoyMnzO2 was obtained by mixing lithium and calcining. In this paper, ternary cathode materials with different ratios of NCM were prepared by the solvothermal method. The structure and morphology of the materials were analyzed by X‐ray diffraction, scanning electron microscopy, and energy‐dispersive spectroscopy. The effects of the ratio on the electrochemical properties of the materials were investigated by constant current charge and discharge test and electrochemical impedance spectroscopy test. The synthesized lithium‐nickel‐cobalt‐manganese oxide belongs to the hexagonal system and has an α‐NaFeO2 layered structure, which is an R‐3m space group. The NCM ternary cathode materials with different morphologies were obtained by changing the ratio of NCM. The sample with NCM ratio of 5:3:2 has a unique sheet‐like spherical shape and has the best rate performance.

MnO/Mn2O3 Nanowires Coated by Porous N-Doped Carbon for Long-Cycle and High-Rate Lithium-Ion Batteries

Manganese oxides with versatile valence display an enormous potential in the lithium-ion battery (LIB) anode materials, but deficient lithium storage capacity, short discharge platform and inferior...

Electron density modulation of GaN nanowires by manganese incorporation for highly high-rate Lithium-ion storage

Gallium nitride (GaN) has high theoretical capacity and low discharge platform. However, it still suffers from poor conductivity and unsatisfactory cycle performance in lithium-ion batteries (LIBs). In this work, the doped manganese (Mn) are realized in GaN nanowires through a simple and straight forward chemical vapor deposition (CVD) process. When the successful Mn doping was carefully examined in structural characterizations, it is discovered at the atomic level that the species of Mn dopants in GaN nanowires only exist in the feature of Mn+ rather than of metallic Mn, which can significantly promote the electrical conductivity and Li-ions transfer. The tested Mn doped GaN nanowire arrays electrode exhibit the capacity up to 780.3 mA h g−1 at 0.1 A g−1 after 100 cycles and 326.8 mA h g−1 at 5.0 A g−1 after 500 cycles, respectively. The tight and direct contact between Mn doped GaN nanowires and graphite layer provides ultrafast electronic transfer. Density functional theory (DFT) studies confirm that Mn covalent doping can generate the change of local atomic arrangement. Moreover, the electronic structure change significantly increase the electrical conductivity for the fast charge transfer efficiency. This covalent doping strategy for the electron densities regulation could boost the Li-ions storage performance for developing advanced electrode materials in energy storage and beyond.

Study on discharge voltage and discharge capacity of LiFe1−xMnxPO4 with high Mn content

Rod-like LiFe1−xMnxPO4/C cathode with particle size of about 300–500 nm was fabricated successfully via simple hydrothermal method. By means of adjusting the manganese content of LiFe1−xMnxPO4, the electrochemical property was studied to clarify the effect of manganese content. LiFe1−xMnxPO4/C sample with x = 0.70 showed the superior specific discharge capacity of 153.1 mAh g−1 at a rate of 0.1 C, and the electrochemical mechanism analyzed by electrochemical impedance spectra demonstrated that the LiFe0.30Mn0.70PO4/C exhibited the smallest charge transfer impedance and the largest lithium-ion diffusion coefficient. With the increase of manganese content, the reduction of discharge capacity is attributed to the linear decrease of Mn2+/Mn3+ reduction reaction. When x = 0.80, the two discharge platforms located at 3.5 and 3.9 V, respectively, reach a maximum, which result from the reduction electromotive force of Fe2+/Fe3+ affected by the addition of manganese ions since the discharge platform of LiMnPO4 is higher than that of LiFePO4.

Cyclic shock damage characteristics of electrohydraulic discharge shockwaves

To improve the quality of electrohydraulic discharge (EHD) shockwaves cracking effect and reduce its damage, the study examines the cumulative damage characteristics of rock induced by shockwaves generated by EHD. Voltage, current, energy, efficiency, wave velocity, and peak value of incident and transmission shockwave of a liquid–solid interface at different discharge energies are given based on the observation of the shockwaves of established discharge platform. The cyclic impact cracking test is conducted on cement samples. The cement samples are effectively cracked, and the surface formed several cracks. The tests results indicate that the cumulative effects of different cyclic loading modes exist under the action of EHD shockwaves. An upper limit exists on the cumulative effect, and the breakdown voltage affects the maximum effective number of discharges and affects the depth of action. Particle flow code 2D (PFC2D) simulation is used to simulate the cement samples under the same experimental conditions. The development process and shape distribution of the internal microcracks under different loading energies and loading times are analyzed. The results indicate that there are three cumulative effects of microcrack development stages (i.e. microcrack accumulation, cracks development, and slowing down and cessation of crack development). Simultaneously, the results suggest that the cumulative damage effect of EHD shockwave on rock materials can be divided into three zones (i.e. crushing zone, crack zone, and elastic zone), which can be effectively adjusted via controlling the loading voltage, loading times, and working distance. Finally, an experiment-simulation combined control strategy is proposed to avoid the crushing zone and raise the crack zone. The study provides theoretical, experimental and simulation guidance for the application of EHD shockwaves.

First-principles study of the adsorption behaviors of Li atoms and LiF on the CF x (x = 1.0, 0.9, 0.8, 0.5, ∼0.0) surface.

Based on first principles calculation, the adsorption properties of Li atoms and LiF molecules on the fluorographene (CFx) surface with different F/C ratios (x = 1.0, 0.9, 0.8, 0.5 and ∼0.0) have been studied in the present work. The calculated binding energy of Li and CFx is greater than 2.29 eV under different F/C ratios, indicating that the battery has the potential to maintain a high discharge platform during the whole discharge process. But the adsorption energies of LiF on a CFx layer for different F/C ratios are 0.12–1.04 eV, which means LiF is not easy to desorb from a CFx surface even at room temperature. It will stay on the surface for a long time and affect the subsequent discharge. Current calculations also show the structure of the CFx-skeleton will change greatly during the reaction, when there are many unsaturated carbon atoms on the CFx surface, such as at x = 0.8 and 0.5. Moreover, the discharge voltage is strongly dependent on the discharge site. After discharge, the CFx-skeleton may continue to relax and release a lot of heat energy.

Effect of 100-nm Al2O3 Particle Inclusions on 100-kA Pulsed Arc Erosion of W–Cu Electrodes

Erosion resistance of electrode materials is one of the key factors affecting the performance and working life of gap switches. In order to explore whether the electrode material with added nanoscale metalloid particles has better erosion resistance under the strong pulse current, a strong current discharge platform was built, and W80/Cu and W80/Cu–Al2O3 were selected as the research objects. The experimental study was carried out under a strong pulse current with a peak value of over 100 kA. By comparing the mass change, the microtopography, and surface roughness of the erosion area, it was found that the addition of nano-Al2O3 particles improved the erosion resistance of the W–Cu alloy. The anode loss was down about 14.7% slightly after adding Al2O3, and the cathode loss of W80/Cu–Al2O3 was down about half. The addition of Al2O3 will increase the working life by 25.3%. Besides, the microstructure of the erosion area became flatter and the roughness was reduced.

Energy storage performance of CuO as a cathode material for aqueous zinc ion battery

Rechargeable aqueous zinc ion batteries (ZIBs) with high specific capacity appear promising to meet the increasing demand for low cost and sustainable energy storage devices. Because the investigation of aqueous ZIBs is still in the incipient stage, the exploration of cathode materials with high specific capacity is necessary. Herein, the CuO nanorods were prepared by a simple liquid phase method and for the first time the CuO/Zn system with high and stable voltage platform was established successfully. The discharge platform is at 0.82 V and remains stable throughout the charge and discharge process. The constant current charge-discharge test shows that the CuO/Zn battery within the voltage of 0.4–1.1 V delivers high reversible capacity of 219 mA h g−1 at 0.3 A g−1. The cyclic voltammogram analysis shows that the Zn-ion storage in CuO is a diffusion-controlled kinetic process. Meanwhile, the phase evolution study during the first charge-discharge cycle reveals that the energy storage mechanism of CuO cathode is conversion reaction. The results demonstrate the feasibility of a conversion reaction energy storage mechanism for zinc ion batteries.

Fe-doped LiMnPO4@C nanofibers with high Li-ion diffusion coefficient

Olivine-type LiMnPO4 (LMP) cathodes have gained enormous attraction for Li-ion batteries (LIBs) due to high discharge platform, theoretical capacity and thermal stability. However, it is still challenging to achieve encouraging Li-storage behavior owing to the low electronic conductivity and slow Li-ion diffusion rate of LMP. Here, the electrochemical behavior of fibrous LiFexMn1-xPO4@carbon (LFxM1-xP@C, x = 0, 0.25, 0.5, 0.75, 1) composites with different Fe doping amounts is investigated. Among the composites, LF0.5M0.5P@C demonstrates a superior cell performance due to a higher Li-ion diffusion coefficient (DLi), resulting from a proper Fe doping ratio and a more uniform morphology. At a current rate of 0.2 C (1 C = 170 mA g−1), the LF0.5M0.5P@C cathode delivers a specific capacity of 150 mAh g−1 up to 500 cycles with a capacity retention of 119%. A longer-term cycling at 5 C for 2000 cycles can be maintained with a reversible capacity exceeding 102 mAh g−1. The fundamental study provides an insightful guidance for future design of cathode materials with high performance.

Fabrication and theoretical investigation of cobaltosic sulfide nanosheets for flexible aqueous Zn/Co batteries

Flexible and recyclable zinc-based batteries have been hot research topics due to their high discharge platform, safety, and low cost. However, most research on zinc-based batteries put their attention on metal oxides as the cathode, such as manganese dioxide (MnO2), cobaltosic oxide (Co3O4), nickel oxide (NiO), etc. Very few studies use metal sulfides as electrode materials and focus on its mechanism based on theoretical analysis. Hence, in this work, we firstly used cobaltosic sulfide (Co3S4) nanosheets grown on Ni foam (CSNSs/NF) as an electrode material for zinc-based batteries. Both first-principles calculations and experimental results reveal that S plays a crucial role in the capacitive activity and electrical conductivity enhancement for Co-based materials. The Zn//CSNSs/NF battery provides a high specific capacity of 317 mA h g−1 at a current density of 1 A g−1. Furthermore, it also displays an impressive energy density of 507 Wh kg−1 and a long cycling performance. Impressively, the Zn//CSNSs/NF battery has high flexibility and can work well under different deformations. This work not only provides a new member of cathode materials in zinc-based batteries, but also opens new opportunities for powering portable and wearable electronics.

Porous Zinc Anode Design for Zn-air Chemistry.

Zinc-air battery has drawn increasing attention from the whole world owing to its large energy capacity, stable working voltage, environmentally friendship, and low price. A special porous Zn with three-dimensional (3D) network frame structure, whose multistage average pore sizes can be tuned from 300 to 8 um, is synthesized in this work. It is found that there is a competition between Zn2+ and for their reduction on the supports. And the decrease of Zn2+ concentration and increase of concentration can facilitate the decrease of pore size. Potential-dynamic polarization was tested with 3-electrodes cell, aiming to characterize the electrochemical activity and corrosion properties of porous Zn and commercial Zn foil electrodes. After optimization, the porous Zn prepared with the parameters of 3 M NaBr, 1 M C2H3O2NH4, and 0.01 M C4H6O4Zn shows the most negative corrosion potential of −1.45 V among all the samples, indicating the remarkable anti-corrosion property. Its discharge specific capacity is up to 812 mAh g−1. And discharge-charge test of the porous Zn shows an initial discharge platform of 1.33 V and an initial charge platform of 1.96 V, performing a small overpotential. What's more, the porous Zn exhibits a much longer cycle life than commercial Zn foil. Our work will not only shed light on the design and synthesis of other porous metal materials, but also further promote the development of Zn-based battery electrochemistry.

Natural marmatite with low discharge platform and excellent cyclicity as potential anode material for lithium-ion batteries

ZnS has high theoretical capacity (962.3 mAh·g−1) and low discharge platform. However, it has poor electrical conductivity and cycling performance for lithium-ion batteries (LIBs). In this study, a natural mineral of ZnS doped with iron called marmatite was discovered. Results indicated that this natural marmatite has a structure similar to that of the ZnS of the Td2-F4-3m space group and also has low discharge platform (<1 V). Compared with pristine, the natural marmatite has superior electrochemical stability (After 1000 cycles at a current density of 2000 mA g−1, a capacity of 651 mAh·g−1 with a reversible capacity retention rate of 94% remained.) and higher capacity (1009 mAh·g−1 at a current density of 200 mA g−1). These results indicated that the natural marmatite exhibits high capacity and excellent cycle performance, demonstrating unique potential for next-generation LIBs.

Molecular Design Strategies for Electrochemical Behavior of Aromatic Carbonyl Compounds in Organic and Aqueous Electrolytes.

To sustainably satisfy the growing demand for energy, organic carbonyl compounds (OCCs) are being widely studied as electrode active materials for batteries owing to their high capacity, flexible structure, low cost, environmental friendliness, renewability, and universal applicability. However, their high solubility in electrolytes, limited active sites, and low conductivity are obstacles in increasing their usage. Here, the nucleophilic addition reaction of aromatic carbonyl compounds (ACCs) is first used to explain the electrochemical behavior of carbonyl compounds during charge–discharge, and the relationship of the molecular structure and electrochemical properties of ACCs are discussed. Strategies for molecular structure modifications to improve the performance of ACCs, i.e., the capacity density, cycle life, rate performance, and voltage of the discharge platform, are also elaborated. ACCs, as electrode active materials in aqueous solutions, will become a future research hotspot. ACCs will inevitably become sustainable green materials for batteries with high capacity density and high power density.