The role of long-period stacking ordered phase on the discharge and electrochemical behaviors of magnesium anode Mg-Zn-Y for the primary Mg-air battery

This work investigated and discussed the role of long-period stacking ordered (LPSO) phase on discharge performance and electrochemical behaviors of Mg-Zn-Y anode for Mg-air battery in detail. The volume fraction of LPSO phase increases with the increasing Y and Zn content. Compared with Mg-2Zn anode, Mg-Zn-Y anode with low content of LPSO phase has better discharge properties due to high open-circuit potential and low corrosion rate. However, anodes contained a high volume of LPSO phase exhibit poor corrosion resistance and discharge properties. The ZW12 alloy shows the best discharge capacity and anodic efficiency as high as 1612.9 mAh·g⁻¹ and 74.49% at the 40 mA·cm⁻². It also outputs a high peak specific energy 1859.15 mWh·g⁻¹ at 10 mA cm⁻², which is 37.56% higher than Mg-2Zn anode and 249.44% higher than ZW39 anode. The LPSO phase totally changes the decomposition process of Mg matrix, displaying the lamellar peeling surface in LPSO-affect zone. This lamellar peeling mode can help to take away the discharge products from the anodic surface, improving the anode performance.     

Achieving high energy efficiency of alkaline hybrid zinc battery by using the optimized Co–Mn spinel cathode

As a potential candidate in the future energy storage system, Zinc-air batteries (ZABs) are impeded by their insufficient discharge voltages and low charge-discharge efficiencies. Building the alkaline hybrid zinc batteries (AHZBs) combining ZAB and alkaline zinc/cobalt batteries (ZCB) at the battery level can supply an effective strategy to solve these problems. In this work, we fabricate a self-supported Mn–Co spinel electrode (named as MnCo₂O₄) with the porous nanofiber morphology by a facile hydrothermal method and assemble AHZB. Thanks to the large electrochemical active surface area and appropriate ratio of Co²⁺/Co³⁺, the as-prepared MnCo₂O₄ electrode shows both the high bifunctional oxygen catalytic activities for ZABs and metal ion redox properties for ZCBs. AHZB with the self-supported MnCo₂O₄ electrode possesses two voltage platforms in both charge and discharge processes due to the oxygen evolution/reduction reactions (OER/ORR) ZABs and metal ion redox reaction in ZCBs. Besides of the highly power density and excellent cyclic stability, the charge-discharge efficiency of our AHZB with the self-supported MnCo₂O₄ electrode can reach 86.2%, almost being the highest value in the recent works. Our work supplies a viable strategy for developing high-performance ZABs with improved discharge voltage and charge-discharge efficiency.     

The effects of current density and amount of discharge on dendrite formation in the lithium powder anode electrode

A compacted lithium powder anode was used to improve the demerits of dendrite formation of lithium metal. Dendrite formation of lithium metal was restrained to use compacted lithium powder anode under a specific amount of discharge and the current density. In this study, the amount of discharge and the current density which suppress dendrite formation at the surface of a lithium powder electrode were investigated on an experimental basis. Discharge/charge reactions were accomplished on various values of the amount of discharge and current density by using beaker cells. It was analyzed by SEM images whether dendrite was formed or not on the surface of lithium powder electrode. From the various experiments, the relationship between current density and total amount of discharge was deduced as a simple mathematical model. From the model, the critical condition of total amount of discharge for dendrite formation in Li-powder electrode was increased from 0.1 mA cm⁻² to 1 mA cm⁻² current density. However, the critical condition of total amount of discharge was decreased over 1 mA cm⁻². Using the model, the condition whether dendrite formed or not on the Li-powder anode could be estimated.     

A comparative study of the effects of surface condition and amalgamation on the corrosion and polarisation characteristics of pure zinc and two battery zinc alloys in leclanche related electrolyte

The effect of surface preparation and amalgamation on the corrosion and polarisation characteristics of pure zinc and two battery zinc alloys (ZnPdCd) and (ZnPbCdFe) has been compared and contrasted in concentrated NH₄Cl solution. Polished metal surfaces have been used to simulate the surface condition of the anode materials during initial battery storage periods and etched surfaces have been used to simulate conditions after high rate discharge. The investigation highlights the extreme sensitivity of the corrosion behaviour to small changes in regard to the high (Pb, Cd) or low (Fe) hydrogen overvoltage components. In order to explain the corrosion characteristics of the etched alloys consideration must be given to the effect of surface accumulation of minor alloying constituents in addition to surface roughness changes. Amalgamation of the polished specimens produces a significant reduction in their corrosion rate. Amalgamation of the etched metals removes the effect of the accumulated minor alloying components Pb and Cd, probably by surface amalgam formation. In the case of the Fe containing alloy, however, the deleterious effects of the surface accumulation of Fe cannot be removed.     

Chrome and cobalt-based novel electrolyte systems for redox flow batteries

In the present work, novel redox ion-pairs (as cobalt and chromium) have been used in aqueous medium for the first time in the literature as electrolyte component of redox flow battery system. The electrochemical performance of the Co(II) and Cr(III) redox species as anolyte and catholyte was investigated by cyclic charge-discharge tests, respectively. Electrochemical behaviors of Cr(III) solutions in sulfuric acid solution were determined by using differential pulse voltammetry, electrochemical impedance spectroscopy and cyclic voltammetry via a typical three-electrode system. Morphological analyses of surface of pencil graphite electrode, which was used as anode in differential pulse voltammetric analysis, were done by scanning electron microscopy. Discharge capacity of the battery system consisting of 1.0 M Cr(III) as anolyte (negative electrolyte) and 1.0 M of Co(II) as catholyte (positive electrolyte) in 4.0 M of sulfuric acid was determined as 682.5 mAh (1.4 Ah L⁻¹) with 4 mA cm⁻² charge current density and 0.4 mA cm⁻² discharge current density. Voltage efficiency, energy efficiency and coulombic efficiency of the battery were 70.1%, 53.8% and 57.2%, respectively. The discharge cell potential of the battery was also determined as 1.40 V.     

Flower-like architecture of CoSn4 nano structure as anode in lithium ion batteries

CoSn₄ nano-particles were synthesized on Cu and Ni substrates through pulsed current electrodeposition and used as anode in lithium ion batteries. Nano particles with Flower-like morphology were obtained through applying an average current density of 85 mA/cm² on Ni substrate while the particles formed using constant current electrodeposition are greater in size ca. 500 nm. Optimum discharge capacity of synthesized CoSn₄ was obtained 848 mAh g^?1 which reduced to 500 mAh g^?1 at 120th cycle indicating an enhanced electrochemical performance compared to anode films synthesized through other pulsed current densities and also constant current electrodeposition. This high discharge capacity and cycleability is attributed to finer crystal grains and flower-like morphology of nano particles. Also, the sample synthesized on Ni substrate showed higher cycleability and noticeably lower resistance. High resistance of anode film synthesized on Cu substrate is due to the corrosion and passivation of copper occurred by HF formation in LiPF₆ electrolyte.     

Study on the electrochemical properties of zinc/polyindole secondary battery

This study is intended to develop an aqueous zinc/polyindole secondary battery system. Polyindole, which is synthesized by chemical oxidation using ammonium peroxydisulfate as oxidants, is used as cathode active materials. Zn foil and ZnCl₂ are used as anode active materials and the electrolytic solution, respectively. FTIR and NMR test are carried out to confirm the polymerization of indole and the chemical structure of polyindole. The performance of zinc/polyindole secondary battery system is evaluated in term of cyclic voltammogram, discharge capacity and durability test. The battery achieves 2.0 V during the charging process and shows about 80-60 Ah kg⁻¹ discharge capacity at discharge current density of 200-1000 A m⁻², respectively. The battery is successively charged and discharged at constant current densities, the discharge capacity density and energy density decreases only by 2.0% and 3.5% at 200th cycle, respectively. This result shows that the zinc/polyindole battery has the good characteristics of charge/discharge performance. With the development of the battery system, this sort of battery would be promising in future applications.     

Effect and mechanism study on buffer layer in secondary Li metal battery

锂金属是已知的理论比容量（3860 mA·h/g）最高的材料,且锂金属具有最低的对氢电位（-3.040 V）和极小的密度（0.53 g/cm³）。所以锂金属是一种极具潜力的电池负极材料。但是锂金属电池存在着很严重的安全问题且循环效率低,所以直到现在还没有正式商用。锂离子电池的发展日趋成熟,但是其容量已经无法满足科技的发展,所以发展下一代电池刻不容缓,而锂金属电池是一个良好的选择。为了克服锂金属负极在应用中存在的问题,本文提出了一种缓冲层结构插入锂金属电池的隔膜与负极之间,并分别将碳纳米管和聚苯胺/碳纳米管复合材料作为缓冲层插入锂电池中。倍率性能测试、循环性能测试和形貌测试均指出,缓冲层结构对锂金属负极的枝晶生长具有抑制作用,从而改善了锂金属电池的安全问题,并对其循环效率具有很大的提升作用。     

In situ STM studies of zinc in aqueous solutions containing PEG DiAcid inhibitor: Correlation with electrochemical performances of zinc–air fuel cells

Electrochemical performance of prismatic zinc–air fuel cells comprising zinc anode gel containing poly(ethylene glycol) (PEG 600) and poly(ethylene glycol) bis(carboxymethyl) ether (PEG DiAcid 600) as corrosion inhibitor were studied. It was found that in addition to the low zinc corrosion rates obtained from cells utilizing PEG DiAcid 600 as corrosion inhibitor, both analog and global mobile system (GSM) discharge capacities and potential plateaus, in a wide range of temperatures were higher once PEG DiAcid was added to the zinc gel mixtures. The results obtained from in situ scanning tunneling microscopy (STM) studies of zinc substrates immersed in deionized (DI) water containing inhibitors reveal that the film produced on the zinc metal in the presence of PEG DiAcid is by far thinner than the film produced by other inhibitors such as PEG 600 and polyoxyethylene alkyl phosphate ester acid (GAFAC RA 600). These studies also reveal that the addition of PEG DiAcid forms an adherent and a complete protective coverage, while the addition of PEG 600 and GAFAC RA 600 resulted in an incomplete coverage with the appearance of pits and terraces, indicating on a restricted inhibition performance of these two polymers compared with PEG DiAcid. These studies suggest a low interface resistivity of zinc immersed in alkaline solution containing PEG DiAcid, which is expressed in a higher working potential and increased cell capacity in different temperatures at two discharge modes of analog and GSM.     

Al-6013-T6 and Al-7075-T7351 alloy anodes for aluminium-air battery

This study is aimed to determine the appropriate anode material (pure Al, 6013-T6; Al1 and 7075-T7351; Al2) for Al-air batteries. Electrochemical Measurements, Galvanostatic Anodic Dissolution Test and Surface Characterization are performed. The corrosion rate and the hydrogen gas evolution rate are calculated. Anodic dissolution test is carried out at the current density of 10–50 mA cm^?2. The weight loss measurements were performed. The anode utilization (Ua%) and capacity density are calculated. The surface morphology of electrodes is investigated by scanning electron microscope (SEM) and mapping imagines are taken. The surface analysis also is performed by energy dispersive X-ray spectrometer (EDS) and contact angles are determined by Young–Laplace Contact Angle method. As a result, it is seen that alloy elements change the surface characteristics during discharging of the battery and the battery performance is positively affected. Especially, copper shows surprisingly synergistic effect with aluminium on the alloy surface.     

Effects of polystyrene sulfonate/graphene and Mn3O4/graphene on property of aluminum(zinc)-air batteries

A polystyrene sulfonate/graphene-based NaOH electrolyte and a Mn₃O₄/graphene catalyst were prepared for fabricating and testing metal-air batteries with pure Al and Zn anodes. Electrochemical performances, corrosion rates and surface morphologies were investigated. The operating voltage, anodic utilization rate and energy density of the assembled aluminum-air battery are 1.167 V, 88% and 2546 Wh·Kg⁻¹, respectively. This overall performance is better than Al-air battery with 4 M NaOH solution and MnO₂ catalyst. Apparently, polystyrene sodium sulfonate/graphene improves the conductivity of the solution and reduces the corrosion rate of aluminum anode, and Mn₃O₄/graphene reduces cathode polarization of air cathode.     

Heat management in aluminium/air batteries: sources of heat

One of the problems with the aluminium/air battery is the generation of heat, during both idle and discharge periods. The main sources of heat are: (i) corrosion of the aluminium anode during the idle period; (ii) inefficient, or less efficient, dissolution of anode during discharge; (iii) Joule heat during discharge, and (iv) non-uniform mass transfer during both dicharge and idle periods. These components of heat act in a cumulative way because they are all interconnected. This paper addresses the basic reasons for the origin of these sources of heat. Suitable and practical remedial measures for the effective removal of such heat in the aluminium/air battery are suggested.     

Functionalized polythiophene-coated textile: A new anode material for a flexible battery

A new all-polymer battery system has been developed. Polypyrrole and styryl-substituted dialkoxyterthiophene (poly(OC₁₀DASTT) are used as the cathode and anode material, respectively. The anode electrode is prepared by directly casting undoped neutral poly(OC₁₀DASTT) from chloroform solution on two different substrates (current-collectors), carbon-fibre mat or Ni/Cu-coated nonwoven polyester. Poly(OC₁₀DASTT) exhibits electroactivity on these two substrates, and batteries containing the polymers show different charge/discharge properties. All the batteries show a high discharge efficiency of over 94%, and a discharge capacity of 39.1 mAh g⁻¹ is obtained for the battery with an anode that consists of poly(OC₁₀DASTT) on Ni/Cu-coated nonwoven polyester.     

Investigation of in-situ polymerization synthesized carbon-coated zinc oxide as anode material for Zn/Ni secondary battery

Using the resorcinol-formaldehyde (RF) resin as carbon source, core-shell structured carbon-coated zinc oxide (ZnO@RFC) was synthesized by cetyltrimethylammonium bromide (CTAB) assisted in-situ polymerization followed with carbonization process. The results showed that the ZnO particles were uniformly coated by an amorphous carbon layer. The excellent structural stability and high electrochemical performance depend it to be designed into carbon shell with a tunable thickness up to 14.4 nm, resulting in the ZnO@RFC anode delivers initial discharge specific capacity of 543 mAh g^?1 and optimized 125 cycle life with capacity retention of 97.5% for Zn/Ni secondary batteries. And the effects of the thickness of carbon shell on electrochemical performance, corrosion and hydrogen evolution reaction are fully investigated. The results indicate that the carbon shell not only improves the electrical conductivity between ZnO particles but also increases the stability of ZnO in electrolyte.     

New dry and wet Zn-polyaniline bipolar batteries and prediction of voltage and capacity by ANN

Chemically synthesized polyaniline doped with perchlorate ion was used as the electroactive material of the cathode in the construction of bipolar rechargeable batteries based on carbon doped polyethylene (CDPE) as a conductive substrate of the bipolar electrodes. A significant improvement in the originally poor adherence between the polymer foil and electroactive material layer of the anode was achieved by chemical pretreatment (etching) and single-sided metallization of the polymer foil with copper. A thin layer of optalloy was electroplated onto the surface of the copper-coated polymer foil to increase the battery overvoltage. A mixture of 1 wt% electrochemically synthesized optalloy, 92 wt% electrochemically synthesized zinc powder, 2 wt% MgO, 4 wt% ZnO and 1 wt% sodium carboxymethyl cellulose (CMC) was used as the anode mixture. Then, the electroactive mixture of the anode was coated onto the metallized surface of the CDPE. Graphite powder was used to coat the other side of the CDPE at 90 °C at 1 t cm⁻² pressure This side was coated with a cathode mixture containing 80 wt% polyaniline powder, 18 wt% graphite powder and 2 wt% acetylene black. The battery electrolyte contained 1 M Zn(ClO₄)₂ and 0.5 M NH₄ClO₄ and 1.0 × 10⁻⁴ M Triton X-100 at pH 3.2. Both 3.2 V dry and wet bipolar batteries were constructed using a bipolar electrode and tested successfully during 200 charge–discharge cycles. The battery possessed a high capacitance of 130 mAh g⁻¹ and close to 100% columbic efficiency. The loss of capacity during charge–discharge cycles for the wet bipolar battery was less than that for the dry bipolar battery. Self-discharge of the dry and wet batteries during a storage time of 30 days was about 0.64% and 0.45% per day, respectively. An artificial neural network (ANN) was used to model the voltage and battery available capacity (BAC) only for the dry bipolar battery at different currents and different times of discharge.     

Performance of Mg-14Li-1Al-0.1Ce as anode for Mg-air battery

In this research, a new Mg-air battery based on Mg-14Li-1Al-0.1Ce was prepared and the battery performance was investigated by constant current discharge test. The corrosion behavior of Mg, AZ31 and Mg-Li-Al-Ce were studied by self-corrosion rate measurement and potentiodynamic polarization measurement. The characteristics of Mg-Li-Al-Ce after discharge were investigated by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that Mg-Li-Al-Ce is more active than Mg and AZ31. The self-corrosion rate is found to be in the order: Mg-Li-Al-Ce < Mg < AZ31. It has been observed that the Mg-air battery based on Mg-Li-Al-Ce offers higher operating voltage, anodic efficiency and capacity than those with Mg and AZ31. SEM and EIS results show that the discharge product of Mg-Li-Al-Ce is loosely adhered to the alloy surface, and thus Mg-Li-Al-Ce could keep high discharge activity during discharge.     

3.0 V-class film-type lithium primary battery with highly improved energy density

Lithium metal is used as an anode material in a 3.0 V-class film-type MnO₂||Li primary battery to increase the operating voltage and discharge capacity for application to active sensor tags of a radio-frequency identification system. A 20-μm thick lithium layer deposited homogeneously on a copper foil is prepared for the purpose of controlling the efficient utilization and lithium handling. A plasticized gel polymer electrolyte filled with SiO₂ particles is also used to enhance the electrochemical stability and safety of the battery. A lithium primary battery with a lithium anode and a nonaqueous electrolyte is fabricated for the first time in the form of a film with a newly designed Nylon 6/Al/polypropylene pouch for perfect shielding. The fabricated 3.0 V-class film-type lithium primary battery passes several safety tests and achieves a discharge capacity and an energy density of more than 9 mAh cm⁻² and 470 Wh L⁻¹, respectively.     

Heterogeneous aging of large-scale flexible lithium-ion batteries based on micro-heterostructures and simulation

To meet application demands of electric vehicles, cathode materials of batteries have to overcome the life limitation and performance attenuation caused by crack propagation on the surface of electrode particles. With the increase of size and power of batteries, the voltage gradient generated by metal foil current collectors with high conductivity cannot be neglected. This study reconstructed a porous microstructure based on images of surface morphologies of lithium manganese oxide particles collected by a field emission-scanning electron microscope. Based on this, a multi-scale and multi-physics simulation model coupling electro-chemo-thermo-mechanical behaviours was developed to predict heterogeneous mechanical stress and capacity loss of a large-scale flexible lithium-ion battery. The results arising from use of the model show that: (1) Lithium in electrode particles cannot be diffused in time under a high-charge and discharge rate, and the capacity loss of the battery is directly proportional to the stress generated on the electrode particles. Capacity loss at discharge rate of 10C is 46% higher than that at the rate of 1C and corresponding stress in the microstructure increases by 16%. (2) In the design of the battery layout adopted in this study, utilization rates of electrodes and temperature fields are highly heterogeneous at the higher rate. Mechanical stress near the tab is 8% higher than that at the bottom edge, and it is speculated that the rate of aging of the tab is 35% higher. (3) Mechanical stress during lithium extraction in the cathode during charge is less than half of that during discharge. Attributed to small influences of material activity and excellent performance of lithium titanate oxide in the anode, capacity loss during charge is only 2%. (4) During discharge, stress in the contact region of between particles is the largest, resulting in the decrease of the activity and the low lithium-ion concentration. This leads to cracks during cyclic charging and discharging, which further decreases the activity of the materials. (5) Heterogeneity in the distribution of lithium-ion concentration with different sizes of particles significantly rises with the rate. The model built in this research couples the analysis of temperature field of a battery cell and stress field of the microstructure, which is conducive to understanding mechanisms underlying performance attenuation of the large-scale flexible lithium-ion battery under high-rate use.     

Life duration of Ni–MH cells for high power applications

Intensive research and development carried out at SAFT Research [1], [2] has shown that limitation of Ni–MH battery life duration can be directly linked to AB₅ alloy corrosion in the negative electrode. A mathematical model taking into account these results has been developed in order to predict battery life as a function of the conditions of utilisation: cycle and calendar life [3].However, the degradation of the negative electrode is the consequence of two phenomena: surface corrosion of the active alloy and decrepitation of alloy particles during cycling. Up to now, only the kinetic law controlling the evolution of the thickness of the corrosion layer could have been quantified [3]. On the other hand, the kinetic law of decrepitation could not be directly measured, but is only fitted by determining the total amount of corrosion.Thus, an in situ method suitable to quantify the electrochemical surface of the alloy has been developed. Therefore, electrochemical impedance spectroscopy (EIS) has been used to follow the degradation of the negative electrode, as a function of depth of discharge (DOD) during cycling. Alloy corrosion measurements and scanning electron microscope (SEM) analyses have been performed to confirm the validity of the method. It has been found that decrepitation is nearly zero for low levels of low DOD (5%).     

In situ observation of lithium dendrite on the electrode in a lithium-ion battery

锂离子电池尽管已成为便携式电子设备的主流电源,也是电动汽车、混合动力汽车等电源的主要选择之一,但依然存在使用过程中因形成锂枝晶而发生内短路的安全隐患。本文设计了一个宏微观实验研究商业用锂离子电池电极材料的充放电循环性能。在常温小电流充放电条件下,实时原位地观测锂枝晶的产生、生长、消融以及死锂残留等过程。实验结果揭示了锂枝晶不仅仅只是大电流过充或低温充电状态下的产物,常温常态小电流充电条件下依然能够生成锂枝晶。实验发现：锂枝晶出现在充电后期,随后直线伸长,尖端区域形貌保持不变;放电时,锂枝晶逐渐消融,尖端区域形貌依然不变,放电结束后电极上有死锂残留。