Three dimensional porous frameworks for lithium dendrite suppression

Lithium metal is a promising anode material owing to its very low electrochemical potential and ultrahigh specific capacity.However,the growth of lithium dendrites could result in a short lifespan,low coulombic efficiency,and potential safety hazards during the progress of lithium plating/stripping.These factors drastically hinder its application in lithium metal batteries.This review focuses on the use of three dimensional(3D)porous host frameworks to improve Li plating/stripping behaviors,accommodate the change in volume,and suppress or block lithium dendrite growth.Various 3D porous frameworks,including the conductive carbon-based,metal-based,and lithiophilic inorganic-compound frameworks are introduced and summarized in detail.The particular functions,relative developments,and optimized strategies of various 3D porous frameworks for lithium deposition/dissolution behaviors are discussed.Moreover,the challenges and promising developments in the field of Li metal anodes will be discussed at the end of this review.

Excitation and Detection of Shear Horizontal Waves with Electromagnetic Acoustic Transducers for Nondestructive Testing of Plates

The fundamental shear horizontal（SH0） wave has several unique features that are attractive for long-range nondestructive testing（NDT）. By a careful design of the geometric configuration, electromagnetic acoustic transducers（EMATs） have the capability to generate a wide range of guided wave modes, such as Lamb waves and shear-horizontal（SH） waves in plates. However, the performance of EMATs is influenced by their parameters. To evaluate the performance of periodic permanent magnet（PPM） EMATs, a distributed-line-source model is developed to calculate the angular acoustic field cross-section in the far-field. Numerical analysis is conducted to investigate the performance of such EMATs with different geometric parameters, such as period and number of magnet arrays, and inner and outer coil widths. Such parameters have a great influence on the directivity of the generated SH0 waves that arises mainly in the amplitude and width of both main and side lobes. According to the numerical analysis, these parameters are optimized to obtain better directivity. Optimized PPM EMATs are designed and used for NDT of strip plates. Experimental results show that the lateral boundary of the strip plate has no perceivable influence on SHO-wave propagation, thus validating their used in NDT. The proposed model predicts the radiation pattern ofPPM EMATs, and can be used for their parameter optimization.

Deep eutectic solvent-based polymer electrolyte for solid-state lithium metal batteries

Poly(ethylene) oxide(PEO)-based electrolytes have been widely studied for solid-state lithium batteries while their ionic conductivity and lithium-ion transference number still need to be further improved.Herein, using the combined experimental and theoretical approach, we demonstrate a novel, solidstate PEO-deep eutectic solvent(DES) electrolyte for the first time. We found that the in situ formation of DES can reduce the crystallinity of PEO matrix and more Li+ions can move freely owing to the weakened coordination between ether oxygens and Li-ions. Besides, we show that more Li+ions can be dissociated from Li salts in PEO-DES electrolyte using the molecular dynamics simulations. Such liquid-free PEO-DES electrolytes showed good ionic conductivity(2.1 × 10^(-4) S cm^(-1)) which is 160% higher than that of conventional PEO-Li TFSI(8.1 × 10^(-5) S cm^(-1)) electrolyte at 60 ℃. Additionally, the PEO-DES electrolyte showed 136% increase of Li-ion transference number(0.33) compared with ionic liquid-doped PEO-Li TFSI(0.14) at 60 ℃. Moreover, the PEO-DES exhibited good compatibility with Li metal and stable Li plating/stripping behavior with little morphology change of Li metal. This research also provides new insights into the enhancement mechanisms of novel polymer electrolytes, improving our fundamental understanding of critical challenges that have impeded the adoption of solid-state lithium metal batteries.

Electrodeposition of a dendrite-free 3D Al anode for improving cycling of an aluminum-graphite battery

Aluminum-metal batteries show great potential as next-generation energy storage due to their abundant resources and intrinsic safety.However,the crucial limitations of metallic Al anodes,such as dendrite and corrosion problems in conventional aluminum-metal batteries,remain challenging and elusive.Here,we report a novel electrodeposition strategy to prepare an optimized 3D Al anode on carbon cloth with an uniform deposition morphology,low local current density,and mitigatory volume change.The symmetrical cells with the 3D Al anode show superior stable cycling(>450 h)and low-voltage hysteresis(~170 mV)at 0.5 mA cm^(−2).High reversibility(~99.7%)is achieved for the Al plating/stripping.The graphite||Al‐4/CC full batteries show a long lifespan of 800 cycles with 54 mAh g^(−1) capacity at a high current density of 1000 mA g^(−1),benefiting from the high capacitive-controlled distribution.This study proposes a novel strategy to design 3D Al anodes for metallic-Al-based batteries by eliminating the problems of planar Al anodes and realizing the potential applications of aluminum-graphite batteries.

The evolution and failure mechanism of lithium metal anode under practical working conditions

Lithium(Li)metal is regarded as a promising anode material to render the Li batteries with high energy density and therefore satisfy the ever-growing energy demands of high-end storage devices[1].Unfortunately,the dendrite growth accompanied with accumulation of"dead Li"leads to low Coulombic efficiency,poor cycling lifespan,and even severe safety hazards,critically hindering the practical implementation of Li metal batteries[2,3].

Porous polymer electrolytes for long-cycle stable quasi-solid-state magnesium batteries

The development of applicable electrolytes is the key point for high-performance rechargeable magnesium batteries(RMBs).The use of liquid electrolyte is prone to safety problems caused by liquid electrolyte leakage.Polymer-based gel electrolytes with high ionic conductivity,great flexibility,easy processing,and high safety have been studied by many scholars in recent years.In this work,a novel porous poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)membrane is prepared by a phase inversion method.By immersing porous PVDF-HFP membranes in MgCl2-AlCl3/TEGDME(Tetraethylene glycol dimethyl ether)electrolytes,porous PVDF-HFP based electrolytes(PPEs)are formed.The PPE exhibits a high ionic conductivity(4.72×10^(-4) S cm-1,25℃),a high liquid electrolyte uptake of 162%,as well as a wide voltage window(3.1 V).The galvanostatic cycling test of Mg//Mg symmetric cell with PPE reveals that the reversible magnesium ion(Mg^(2+))plating/stripping occurs at low overpotentials(~0.13 V).Excellent long cycle stability(65.5 mAh g^(-1) over 1700 cycles)is achieved for the quasisolid-state RMB assembled with MoS2/C cathode and Mg anode.Compared with the liquid electrolyte,the PPE could effectively reduce the side reactions and make Mg^(2+)plating/stripping more uniformly on the Mg electrode side.This strategy herein provides a new route to fabricate high-performance RMB through suitable cathode material and polymer electrolyte with excellent performance.

Emerging rechargeable aqueous aluminum ion battery:Status,challenges,and outlooks

Aluminum ion battery(AIB)technology is an exciting alternative for post-lithium energy storage.AIBs based on ionic liquids have enabled advances in both cathode material development and fundamental understanding on mechanisms.Recently,unlocking chemistry in rechargeable aqueous aluminum ion battery(AAIB)provides impressive prospects in terms of kinetics,cost,safety considerations,and ease of operation.To review the progress on AAIB,we discuss the critical issues on aluminum electrochemistry in aqueous system,cathode material design to overcome the drawbacks by multivalent aluminum ions,and challenges on electrolyte design,aluminum stripping/plating,solid-electrolyte interface(SEI)formation,and design of cathode materials.This review aims to stimulate exploration of high-performance AAIB and rationalize feasibility grounded on underlying reaction mechanisms.

DETECTION OF DELAMINATION IN A COMPOSITE PLATE BY SEM

A numerical method of integration of Green's functions of strip element method (SEM) is proposed The response of ultrasonic source generated by a transducer on the surface of a multi ply composite plate containing a delamination is analyzed by the use of SEM The numerical results show that the scanning features of the ultrasonic waves may be used to identify the delamination inside the composite plate.

Homogenous lithium plating/stripping regulation by a mass-producible Zn particles modified Li-metal composite anode

A stable lithium-metal anode is critical for high performance lithium-metal batteries. However, heterogeneous Li plating/stripping may induce lithium dendrites formation on bare lithium-metal anode, which lowers the cell Coulombic efficiency and weakens battery safety. We found that bare Li metal surface becomes bumpy and cratered with numerous pits formation during Li stripping. These pits enhance electric field distortion and heterogeneous ion distribution during plating. Li plating preferentially happens on the edge of the pits, intensifying the voltage variation and Li dendrites growth, which leads to the cell rapid death or separator piercing. Herein, we propose a facile and mass-producible method to homogenize Li plating/stripping via adding lithiophilic particles into Li metal. Zinc particles were uniformly pressed in Li metal by a facile and scalable physical strategy of “rolling”, and transformed into LiZn alloy in situ through Li-Zn alloying at room temperature in a few minutes. The critical role of modified LiZn/Li composite anode in stabilizing electrode surface was revealed by both electrochemical test and simulation. Compared with bare Li anode, the evenly dispersed LiZn alloy particles in Li metal can effectively regulate the Li plating/stripping on electrode surface, reducing deepness of pits during stripping and directionally inducing Li plating to maintain electrode surface stability. On this basis, the pits depth of LiZn/Li composite during Li stripping is reduced to ∼ 15 μm, which is much shallower than that of bare Li metal of ∼ 40 μm. The LiZn/Li composite electrode can stably cycle for 600 h under Li plating/stripping capacity of 1 mAh·cm−2 and current density of 1 mA·cm−2 without any short circuit. Furthermore, assembled LiZn/Li||LiFePO4 full cell presents better cycling stability and rate performances than that of based on bare Li anode.

Insights into interfacial speciation and deposition morphology evolution at Mg-electrolyte interfaces under practical conditions

Rechargeable magnesium(Mg)battery technologies show the promise of low cost,less safety concerns and relatively higher energy density.Interrogating the critical issues on the Mg stripping/plating performance as well as the Mg metal anode-electrolyte interfacial chemistry is one great importance under the practical areal capacity and rate conditions.In this work,we systematically investigate the electrochemistry of Mg stripping/plating processes within four distinctive Mg-ion electrolytes and the Mg anodeelectrolyte interfacial chemistry under practical conditions.Electrochemical results show that the cycle life of Mg//Cu asymmetric cells using these above electrolytes is significantly shortened(less than 10 cycles)when tested at a practical areal capacity of 10 mAh cm^-2.Further optical and electron microscopic analyses reveal that the gradual growth of the Mg deposits is susceptible to detachment from the copper substrate,where the initial nucleation process might occur.In spite of showing an interconnected particle-like morphology,the Mg deposits could easily penetrate the porous separator,leading to cell failure.The co-deposition of metallic Al is revealed from surface region to bulk,while the Cl-containing species exist in the near surface of Mg deposits.Our work not only highlights the critical impacts of areal capacity on the performances of Mg stripping/plating process,but calls for further efforts to eliminating the safety concerns of Mg anode under practical conditions.

Optimization of two-dimensional solid-state electrolyte-anode interface by integrating zinc into composite anode with dual-conductive phases

Solid-state electrolytes(SSEs)are a solution to safety issues related to flammable organic electrolytes for Li batteries.Insufficient contact between the anode and SSE results in high interface resistance,thus causing the batteries to exhibit high charging and discharging overpotentials.Recently,we reduced the overpotential of Li stripping and plating by introducing a high proportion of dual-conductive phases into a composite anode.The current study investigates the interface resistance and stability of a composite electrode modified with Zn and a lower proportion of dual-conductive phases.Zn-cation-adsorbed Prussian blue is synthesized as an intermediate component for a Zn-modified composite electrode(Li-FeZnNC).The Li-FeZnNC symmetric cell presents a lower interface resistance and overpotential compared with Li-FeNC(without Zn modification)and Li-symmetric cells.The Li-FeZnNC symmetric cell shows high electrochemical stability during Li stripping and plating at different current densities and high stability for 200 h.Full batteries with a Li-FeZnNC composite anode,garnet-type SSE,and LiFePO4 cathode show low charging and discharging overpotentials,a capacity of 152 mAh g^(−1),and high stability for 200 cycles.

Recent advances and perspectives for Zn-based batteries:Zn anode and electrolyte

Zn-based batteries have attracted extensive attention due to their high theoretical energy density,safety,abundant resources,environmental friendliness,and low cost.They are a new energy storage and conversion technology with significant development potential and have been widely used in renewable energy and portable electronic devices.Considerable attempts have been devoted to improving the performance of Zn-based batteries.Specifically,battery cycle life and energy efficiency can be improved by electrolyte modification and the construction of highly efficient rechargeable Zn anodes.This review compiles the progress of the research related to Zn anodes and electrolytes,especially in the last five years.This review will introduce fundamental concepts,summarize recent development,and inspire further systematic research for high-performance Zn-based batteries in the future.

Present and future of functionalized Cu current collectors for stabilizing lithium metal anodes

Li metal has been recognized as the most promising anode materials for next-generation high-energy-density batteries,however,the inherent issues of dendrite growth and huge volume fluctuations upon Li plating/stripping normally result in fast capacity fading and safety concerns.Functionalized Cu current collectors have so far exhibited significant regulatory effects on stabilizing Li metal anodes(LMAs),and hold a great practical potential owing to their easy fabrication,low-cost and good compatibility with the existing battery technology.In this review,a comprehensive overview of Cu-based current collectors,including planar modified Cu foil,3D architectured Cu foil and nanostructured 3D Cu substrates,for Li metal batteries is provided.Particularly,the design principles and strategies of functionalized Cu current collectors associated with their functionalities in optimizing Li plating/stripping behaviors are discussed.Finally,the critical issues where there is incomplete understanding and the future research directions of Cu current collectors in practical LMAs are also prospected.This review may shed light on the critical understanding of current collector engineering for high-energy-density Li metal batteries.

Infiltrating lithium into carbon doth decorated with zinc oxide arrays for dendrite-free lithium metal anode

Lithium metal anode for batteries has attracted extensive attentions, but its application is restricted by the hazardous dendritic Li growth and dead Li formation. To address these issues, a novel Li anode is developed by infiltrating molten Li metal into conductive carbon cloth decorated with zinc oxide arrays. In carbonate-based electrolyte, the symmetric cell shows no short circuit over 1,500 h at 1 mA·cm^-2, and stable voltage profiles at 3 mA cm^-2 for ~ 300 h cycling. A low overpotential of ~ 243 mV over 350 cycles at a high current density of 10 mA·cm^-2 is achieved, compared to the seriously fluctuated voltage and fast short circuit in the cell using bare Li metal. Meanwhile, the asymmetric cell withstands 1,000 cycles at 10 C (1 C = 167 mAh·g^-1) compared to the 210 cycles for the cell using bare Li anode. The excellent performance is attributed to the well-regulated Li plating/stripping drive n from the formation of LiZn alloy on the wavy carb on fibers, resulting in the suppress!on of dendrite growth and pulverization of the Li electrode during cycling.

内层锌锂成核位点和外层富含氟化锂保护组织的混合表面膜提高锂阳极循环性能

锂金属阳极具有高活性,易与电解液反应并产生锂枝晶,因而很难实际应用.本文提出在锂阳极表面构建表面膜的解决方案.将含三氟甲烷磺酸锌(Zn(OTF)_(2))和氟代碳酸乙烯酯(FEC)的溶液滴加到锂阳极表面,形成化学组成与结构独特的表面膜(由内层活性成核位点的锌锂合金和外层起保护作用的氟化锂/聚合物组成的复合膜).内层锌锂合金由金属锂与Zn(OTF)_(2)反应形成,为锂沉积/溶解提供了低极化的成核活性位点;外层氟化锂/聚合物由金属锂与FEC反应形成,对锂阳极底层的锌锂合金和金属锂起保护作用,同时对锂阳极充放电过程中产生的体积变化起缓冲作用.锂-锂对称电池和锂-磷酸亚铁锂全电池充放电测试表明,这种独特的表面膜能够显著提高锂金属阳极的循环稳定性,同时降低沉积/溶解过电位.

A hydrophobic artificial solid-interphase-protective layer with fast self-healable capability for stable lithium metal anodes

Lithium(Li)metal has been considered as one of the most promising anodes for high-energy-density batteries.However,the hyperactivity of metallic Li and its dendrite growth are the major hurdles to its practical applications.Herein,a multi-functional solid-interphase-protective layer with excellent waterproof performance and fast self-healing properties was modified on the surface of Li metal to address the above issues.Under the protection of this interface,the metallic Li(denoted as P-Li)exhibited superior electrochemical stability in both Li/Li symmetric cells and full cells.Notably,even after being exposed to humid air for 3 h,the LiFePO_(4)||Li full battery with P-Li anodes still showed long-term stability with a transcendental capacity retention of~100% after 100 cycles,revealing a significant advantage to the non-working LiFePO_(4)||Li battery with air-exposed bare Li anodes.

Development of China's Copper Plate and Strip Industry——Part Ⅱ

In China,the upstream industries of copper processing are copper ore dressing and copper smelting industries.But China’s copper industry has seen unbalanced development between the three steps:copper ore dressing,copper smelting and processing.The industrialpattern where processing capacity is greater than smelting capacity,and smelting capacity

Development of China's Copper Plate and Strip Industry——Part Ⅰ

As a metal,copper comes in third only to iron and aluminum in terms of importance in national economy and as a non-ferrous metal,it ranks second in terms of consumption.The copper industry is a pillar of the non-ferrous metal industry in China.In 2016,the copper industry’s assets accounted for23%of the national non-ferrous industry’s total,and its income accounted for 35%.China also holds

An Anionic Covalent Organic Framework as an Electrostatic Molecular Rectifier for Stabilizing Mg Metal Electrodes

Despite its potential as a high-capacity battery electrode,magnesium(Mg)metals are highly susceptible to electrolytes,resulting in the formation of unwanted passivation layers,which hinder charge transfer phenomena.Here,we first report an anionic covalent organic framework(a-COF)as an electrostatic molecular rectifier(that can preferentially trap solvent molecules)to stabilize Mg metal electrodes.Compared to a neutral COF(n-COF)as a control sample,the a-COF enhances Mg^(2+)transport by facilitating the desolvation of Mg^(2+)-solvent complexes and cationic mobility through its negatively charged one-dimensional columns,thereby achieving an ionic conductivity eight times higher than that of the n-COF.In addition,the anionic porous frameworks in contact with Mg metal electrodes enable a uniform Mg^(2+)flux and interfacial stability with Mg metal electrodes.Consequently,the a-COF exhibited reversible Mg plating/stripping cyclability on Mg metal electrodes compared to the n-COF,demonstrating the electrochemical viability of the anionic frameworks for Mg metal electrode stabilization.