Recent advances in quantifying the inactive lithium and failure mechanism of Li anodes in rechargeable lithium metal batteries

Lithium metal is considered as the ultimate anode material for the next generation of high-energy density batteries.However,non-uniform lithium dendrite growth,serious electrolyte consumption,and significant volume changes during lithium deposition/stripping processes lead to sustained accumulation of inactive lithium and poor cycling reversibility.Quantifying the formation and evolution of inactive lithium under different conditions and fully evaluating the complex failure modes are the key issues in this challenging field.This article comprehensively reviews recent research progress on the quantification of formation and evolution of inactive lithium detected by different quantitative techniques in rechargeable lithium metal batteries.The key research challenges such as failure mechanism,modification strategies and operando characterization of lithium metal anodes are systematically summarized and prospected.This review provides a new angle of view to understand failure mechanism of lithium metal anodes and inspiration and guidance for the future development of rechargeable lithium metal batteries.

Rational design of carbon skeleton interfaces for highly reversible sodium metal battery anodes

Sodium metal batteries(SMBs)have attracted increasing attention over time due to their abundance of sodium resources and low cost.However,the widespread application of SMBs as a viable technology remains a great challenge,such as uneven metallic deposition and dendrite formation during cycling.Carbon skeletons as sodiophilic hosts can alleviate the dendrite formation during the plating/stripping.For the carbon skeleton,how to rationalize the design sodiophilic interfaces between the sodium metal and carbon species remains key to developing desirable Na anodes.Herein,we fabricated four kinds of structural features for carbon skeletons using conventional calcination and flash Joule heating.The roles of conductivity,defects,oxygen content,and the distribution of graphite for the deposition of metallic sodium were discussed in detail.Based on interface engineering,the J1600 electrode,which has abundant Na-C species on its surface,showed the highest sodiophilic.There are uniform and rich F-Na species distributed in the inner solid electrolyte interface layer.This study investigated the different Na-deposition behavior in carbon hosts with distinct graphitic arrangements to pave the way for designing and optimizing advanced electrode materials.

Magnetic resonance imaging techniques for lithium-ion batteries:Principles and applications

Operando monitoring of internal and local electrochemical processes within lithium-ion batteries(LIBs)is crucial,necessitating a range of non-invasive,real-time imaging characterization techniques including nuclear magnetic resonance(NMR)techniques.This review provides a comprehensive overview of the recent applications and advancements of non-invasive magnetic resonance imaging(MRI)techniques in LIBs.It initially introduces the principles and hardware of MRI,followed by a detailed summary and comparison of MRI techniques used for characterizing liquid/solid electrolytes,electrodes and commercial batteries.This encompasses the determination of electrolytes'transport properties,acquisition of ion distribution profile,and diagnosis of battery defects.By focusing on experimental parameters and optimization strategies,our goal is to explore MRI methods suitable to a variety of research subjects,aiming to enhance imaging quality across diverse scenarios and offer critical physical/chemical insights into the ongoing operation processes of LIBs.

Synthesis strategies of hard carbon anodes for sodium-ion batteries

Sodium-ion battery(SIB)is an ideal candidate for large-scale energy storage due to high abundant sodium sources,relatively high energy density,and potentially low costs.Hard carbons,as one of the most promising anodes,could deliver high plateau capacities at low potentials,which boosts the energy densities of SIBs.Their slope capacities have been demonstrated from the defect adsorption of sodium ions,while the plateau capacity depends highly on intercalation and pore filling.Nevertheless,the specific structures of sodium ions stored in hard carbons have not been clarified,namely active sites of adsorption,intercalation,and pore-filling mechanisms.Therefore,delicate synthesis methods are required to prepare hard carbons with controllable specific structures,along with elucidating the precise active sites for enhancing the Na-ion storage performance.To offer databases for future designs,we summarized the synthesis strategies of hard carbon anodes for constructing active sites of plateau capacities.Synthesis methods were highlighted with corresponding influences on the meticulous structures of hard carbons and Na-ion storage behaviors.Last but not least,perspectives were proposed for developing hard carbon anodes from the points of research and practical applications.

Tracking gassing behavior in pouch cell by operando on-line electrochemical mass spectrometry

As the rapid development of more powerful and safer lithiumion batteries, the mechanism study of gases evolution is attacking more and more attention in recent years. Especially under overcharge/discharge and/or high-temperature working condition.

Homogenous metallic deposition regulated by abundant lithiophilic sites in nickel/cobalt oxides nanoneedle arrays for lithium metal batteries

Although lithium(Li)metal delivers the highest theoretical capacity as a battery anode,its high reactivity can generate Li dendrites and"dead"Li during cycling,resulting in poor reversibility and low Li utilization.Inducing uniform Li plating/stripping is the core of solving these problems.Herein,we design a highly lithiophilic carbon film with an outer sheath of the nanoneedle arrays to induce homogeneous Li plating/stripping.The excellent conductivity and 3D framework of the carbon film not only offer fast charge transport across the entire electrode but also mitigate the volume change of Li metal during cycling.The abundant lithiophilic sites ensure stable Li plating/stripping,thereby inhibiting the Li dendritic growth and"dead"Li formation.The resulting composite anode allows for stable Li stripping/plating under 0.5 mA cm^(-2) with a capacity of 0.5 mA h cm^(-2) for 4000 h and 3 mA cm^(-2) with a capacity of3 mA h cm^(-2) for 1000 h.The Ex-SEM analysis reveals that lithiophilic property is different at the bottom,top,or channel in the structu re,which can regulate a bottom-up uniform Li deposition behavior.Full cells paired with LFP show a stable capacity of 155 mA h g^(-1) under a current density of 0.5C.The pouch cell can keep powering light-emitting diode even under 180°bending,suggesting its good flexibility and great practical applications.

Toluene methylation with syngas to para‐xylene by bifunctional ZnZrO_(x)‐HZSM‐5 catalysts

Toluene methylation with methanol on H‐ZSM‐5(Z5)zeolite for the directional transformation of toluene to xylene has been industrialized.However,great challenges remain because of the high energy barrier of methanol deprotonation to the methoxy group,the side reaction of methanol to olefins,coke formation,and the deactivation of zeolites.Herein,we report the toluene methylation coupled with CO hydrogenation to showcase an enhancement in para‐xylene(PX)selectivity by employing a bifunctional catalyst composed of ZnZrO_(x)(ZZO)and modified Z5.The results showed that a PX selectivity of up to 81.8%in xylene and xylene selectivity of 64.8%in hydrocarbons at 10.3%toluene conversion can be realized over the bifunctional catalyst on a fixed‐bed reactor.The selectivity of gaseous hydrocarbons decreased to 10.9%,and approximately half of that was observed in methanol reagent route where the PX selectivity in xylene was 38.8%.We observed that the acid strength,the quantity ratio of Brönsted and Lewis acid sites,and the pore size of zeolites were essential for the PX selectivity.The investigation of the H_(2)/D_(2) kinetic isotope effect revealed that the newborn methyl group in xylene resulted from the hydrogenation of CO rather than toluene disproportionation.Furthermore,the catalyst showed no evident deactivation within the 100 h stability test.The findings offer a promising route for the production of value‐added PX with high selectivity via toluene methylation coupled with syngas conversion.

Understanding the solvation structures of glyme-based electrolytes by machine learning molecular dynamics

Glyme-based electrolytes are of great interest for rechargeable lithium metal batteries due to their high stability,low vapor pressure,and non-flammability.Understanding the solvation structures of these electrolytes at the atomic level will facilitate the design of new electrolytes with novel properties.Recently,classical molecular dynamics(CMD)and ab initio molecular dynamics(AIMD)have been applied to investigate electrolytes with complex solvation structures.On one hand,CMD may not provide reliable results as it requires complex parameterization to ensure the accuracy of the classical force field.On the other hand,the time scale of AIMD is limited by the high cost of ab initio calculations,which causes that solvation structures from AIMD simulations depend on the initial configurations.In order to solve the dilemma,machine learning method is applied to accelerate AIMD,and its time scale can be extended dramatically.In this work,we present a computational study on the solvation structures of triglyme(G3)based electrolytes by using machine learning molecular dynamics(MLMD).Firstly,we investigate the effects of density functionals on the accuracy of machine learning potential(MLP),and find that PBE-D3 shows better accuracy compared to BLYP-D3.Then,the densities of electrolytes with different concentration of LiTFSI are computed with MLMD,which shows good agreement with experiments.By analyzing the solvation structures of 1 ns MLMD trajectories,we found that Li+prefers to coordinate with a G3 and a TFSI−in equimolar electrolytes.Our work demonstrates the significance of long-time scale MLMD simulations for clarifying the chemistry of non-ideal electrolytes.

Patterning with Organized Molecules

Decades of progress in the semiconductor industry has led to lithographically printed dimensions that are small enough that the positions of individual molecules and the stochastic variation in the number of photons have a significant effect on the quality of photoresist patterns.These effects scale badly and will be more important as feature sizes continue to shrink.Selforganizing materials can provide regular patterns of molecules that have the potential to minimize stochastic effects.Some such reported materials are block copolymers,bottle brush polymers and DNA,all of which have been used as part of lithographic patterning.A key challenge for selforganizing materials is defect levels.The energy to rearrange has to be high enough that random defects aren’t created thermally but low enough that rearrangement into preferred domains can occur.All of the methods can generate accurate CDs based on the chemical composition of the material,but they all need some way to control the positions of the feature edges.There are methods for guiding the self-organization,but the final position is the sum of the guide pattern misalignment and the intrinsic alignment error of the self-organizing materials.Thus it can be worse than the positioning of the guide structures.Alignment and defect levels are thus two big challenges for manufacturing introduction of self-organizing materials.

Constructing machine learning potential for metal nanoparticles of varying sizes via basin-hoping Monte Carlo and active learning

Nanoparticles,distinguished by their unique chemical and physical properties,have emerged as focal points within the realm of materials science.Traditional theoretical approaches for atomic simulations mainly include empirical force field and ab initio simulations,with the former offering efficiency but limited reliability,and the latter providing accuracy but restricted to systems of relatively small sizes.Herein,we propose a systematic strategy and automated workflow designed for collecting a diverse types of atomic local environments within a training dataset.This includes small nanoclusters,nanoparticles,as well as surface and bulk systems with periodic boundary conditions.The objective is to construct a machine learning potential tailored for pure metal nanoparticle simulations of varying sizes.Through rigorous validation,we have shown that our trained machine learning potential is capable of effectively driving molecular dynamics simulations of nanoparticles across a wide temperature range,especially within the nanoscale regime.Remarkably,this is achieved while preserving the accuracy typically associated with ab initio methods.

Screening of transition metal oxides for electrocatalytic nitrate reduction to ammonia at large currents

Electrochemical nitrate reduction reaction(NO_(3)RR)towards ammonia,as an emerging and appealing technology alternative to the energy-intensive Haber-Bosch process and inefficient nitrogen reduction reaction,has recently aroused wide concern and research.However,the current research of the NO_(3)RR towards ammonia lacks the overall performance comparison of various electrocatalysts.Given this,we here make a comparison of 12 common transition metal oxide catalysts for the NO_(3)RR under a high cathodic current density of 0.25 A·cm^(-2),wherein Co_(3)O_(4) catalyst displays the highest ammonia Faradaic efficiency(85.15%)and moderate activity(ca.-0.25 V vs.reversible hydrogen electrode).Other external factors,such as nitrate concentrations in the electrolyte and applied potential ranges,have also been specifically investigated for the NO_(3)RR.

A breathable, designable and flexible leather–heater used in wearable thermotherapy

Flexible heaters with personal thermal management capabilities have great potential in thermal therapy applications due to their excellent flexibility, low power consumption, and portability. However, manufacturing wearable heating devices that are breathable, wear resistant and conformal for long-term use is still challenging. To address these issues, we designed a leather heater using breathable, biocompatible, and tailorable leather as the substrate through a simple in-situ polymerization polypyrrole strategy. This heater exhibits excellent heating and mechanical properties(reaching 64℃ at a voltage of 5 V with efficient Joule heat generation of 2286 W/m^(2)and uniform temperature distribution, and functioning properly after 1000 cycles of bendability tests). In addition, this heater displays better wear resistance and water vapor permeability rate(38.04 g/(m^(2)h)). The cuttable and sewable of leather gives the strategy ability to be flexibly designed to mold the heater to the specific requirements of different body parts, providing a new approach to wearable thermal therapy.

Light-responsive and corrosion-resistant gas valve with non-thermal effective liquid-gating positional flow control

Safe and precise control of gas flow is one of the key factors to many physical and chemical processes,such as degassing,natural gas transportation,and gas sensor.In practical application,it is essential for the gas-involved physicochemical process to keep everything under control and safe,which significantly relies on the controllability,safety,and stability of their valves.Here we show a light-responsive and corrosion-resistant gas valve with non-thermal effective liquid-gating positional flow control under a constant pressure by incorporating dynamic gating liquid with light responsiveness of solid porous substrate.Our experimental and theoretical analysis reveal that the photoisomerization of azobenzene-based molecular photoswitches on the porous substrate enabled the gas valve to possess a light-responsive and reversible variation of substantial critical pressure of non-thermal effective gas flow switch.Moreover,the chemically inert gating liquid prevented the solid substrate from corrosion and,by combining with the high spatiotemporal resolution of light,the gas valve realizes a precisely positional open and close under a steady-state pressure.The application demonstrations in our results show the potentials of the new gas valve for bringing opportunities to many applications,such as gas-involved reaction control in microfluidics,soft actuators,and beyond.

Cell osteogenic bioactivity mediated precisely by varying scaled micro-pits on ordered micro/nano hierarchical structures of titanium

Hierarchical surface structures with micro–nano scale play a crucial role in regulation of cell proliferation and osteogenic differentiation.It has been proven that cells are extremely sensitive to the nanoscaled structure and show multifarious phenotypes.Though a vital function of microstructure on osseointegration has been confirmed,the cell performances response to different microscaled structure is needed to be further dissected and in depth understood.In this work,the ordered micro–nano hierarchical structures with varying micro-scaled pits were precisely fabricated on titanium successfully by the combination of electrochemical,chemical etching and anodization as well.In vitro systematical assessments indicated that the micro–nano multilevel structures on titanium exhibited excellent cells adhesion and spreading ability,as well as steerable proliferation and osteogenic differentiation behaviors.It is shown that smaller micro-pits and lower roughness of the hierarchical structures enabled faster cell propagation.Despite cell growth was delayed on micro–nano titanium with relatively larger cell-match-size micro-pits and roughness,osteogenic-specific genes were significantly elevated.Furthermore,the alkaline phosphatase activity,collagen secretion and extracellular matrix mineralization of MC3T3-E1 on multiscaled titanium were suppressed by a large margin after adding IWP-2(an inhibitor of Wnt/b-catenin signal pathway),indicating this pathway played a crucial part in cell osteogenic differentiation modulated by micro–nano structures.

Antibacterial evaporator based on reduced graphene oxide/polypyrrole aerogel for solar-driven desalination

Solar-driven water evaporation is a sustainable method to purify seawater.Nevertheless,traditional volumetric water-evaporation systems suffer from the poor sunlight absorption and inefficient light-to-thermal conversion.Also,their anti-bacterial and antifouling performances are crucial for the practical application.Herein,we introduce reduced graphene oxide(RGO)with broadband absorbance across the entire solar spectrum,and polypyrrole(PPy),an antibacterial polymer with efficient solar absorption and low thermal conductivity,to develop integrated RGO/PPy aerogel as both the solar absorber and evaporator for highly efficient solar-driven steam generation.As a result,the RGO/PPy aerogel shows strong absorption and good photothermal performance,leading to an evaporation rate of 1.44 kg·m^(−2)·h^(−1)and high salt rejection(up to 99.99%)for real seawater,with photothermal conversion efficiency>90%under one sun irradiation.The result is attributed to the localized heat at the air-water interface by the RGO/PPy and its porous nature with functional groups that facilitates the water evaporation.Moreover,the RGO/PPy demonstrates excellent durability and antibacterial efficiency close to 100%for 12 h,crucial characteristics for longterm application.Our well-designed RGO/PPy aerogel with efficient water desalination performance and antibacterial property provides a straightforward approach to improve the solar-driven evaporation performance by multifunctional materials integration,and offers a viable route towards practical seawater desalination.

Building better solid-state batteries with silicon-based anodes

Silicon(Si)-based solid-state batteries(Si-SSBs)are attracting tremendous attention because of their high energy density and unprecedented safety,making them become promising candidates for next-generation energy storage systems.Nevertheless,the commercialization of Si-SSBs is significantly impeded by enormous challenges including large volume variation,severe interfacial problems,elusive fundamental mechanisms,and unsatisfied electrochemical performance.Besides,some unknown electrochemical processes in Si-based anode,solid-state electrolytes(SSEs),and Si-based anode/SSE interfaces are still needed to be explored,while an in-depth understanding of solid–solid interfacial chemistry is insufficient in Si-SSBs.This review aims to summarize the current scientific and technological advances and insights into tackling challenges to promote the deployment of Si-SSBs.First,the differences between various conventional liquid electrolyte-dominated Si-based lithium-ion batteries(LIBs)with Si-SSBs are discussed.Subsequently,the interfacial mechanical contact model,chemical reaction properties,and charge transfer kinetics(mechanical–chemical kinetics)between Si-based anode and three different SSEs(inorganic(oxides)SSEs,organic–inorganic composite SSEs,and inorganic(sulfides)SSEs)are systemically reviewed,respectively.Moreover,the progress for promising inorganic(sulfides)SSE-based Si-SSBs on the aspects of electrode constitution,three-dimensional structured electrodes,and external stack pressure is highlighted,respectively.Finally,future research directions and prospects in the development of Si-SSBs are proposed.

Stabilizing layered superlattice MoSe_(2) anodes by the rational solvation structure design for low-temperature aqueous zinc-ion batteries

Aqueous zinc-ion batteries(AZIBs)have attracted widespread attention due to their intrinsic merits of low cost and high safety.However,the poor thermodynamic stability of Zn metal in aqueous electrolytes inevitably cause Zn dendrites growth and interface parasitic side reactions,resulting in unsatisfactory cycling stability and low Zn utilization.Replacing Zn anode with intercalation-type anodes have emerged as a promising alternative strategy to overcome the above issues but the lack of appropriate anode materials is becoming the bottleneck.Herein,the interlayer structure of MoSe_(2) anode is preintercalated with long-chain polyvinyl pyrrolidone(PVP),constructing a periodically stacked p-MoSe_(2)superlattice to activate the reversible Zn^(2+) storage performance(203 mAh g^(−1)at 0.2 A g^(−1)).To further improve the stability of the superlattice structure during cycling,the electrolyte is also rationally designed by adding 1,4-Butyrolactone(γ-GBL)additive into 3 M Zn(CF_(3)SO_(3))_(2),in whichγ-GBL replaces the H2O in Zn^(2+) solvation sheath.The preferential solvation ofγ-GBL with Zn^(2+)effectively reduces the water activity and helps to achieve an ultra-long lifespan of 12,000 cycles for p-MoSe_(2).More importantly,the reconstructed solvation structure enables the operation of p-MoSe_(2)||ZnxNVPF(Na3V2(PO4)2O_(2)F)AZIBs at an ultra-low temperature of−40°C,which is expected to promote the practical applications of AZIBs.

Structure development of carbon-based solar-driven water evaporation systems

Pressing need goes ahead for accessing freshwater in insufficient supply countries and regions,which will become a restrictive factor for human development and production.In recent years,solar-driven water evaporation(SDWE)systems have attracted increasing attention for their specialty in no consume conventional energy,pollution-free,and the high purity of fresh water.In particular,carbon-based photothermal conversion materials are preferred light-absorbing material for SDWE systems because of their wide range of spectrum absorption and high photothermal conversion efficiency based on superconjugate effect.Until now,many carbon-based SDWE systems have been reported,and various structures emerged and were designed to enhance light absorption,optimize heat management,and improve the efficient water transport path.In this review,we attempt to give a comprehensive summary and discussions of structure progress of the carbon-based SDWE systems and their working mechanisms,including carbon nanoparticles systems,single-layer photothermal membrane systems,bi-layer structural photothermal systems,porous carbon-based materials systems,and three dimensional(3D)systems.In these systems,the latest 3D systems can expand the light path by allowing light to be reflected multiple times in the microcavity to increase the light absorption rate,and its large heat exchange area can prompt more water to evaporate,which makes them the promising application foreground.We hope our review can spark the probing of underlying principles and inspiring design strategies of these carbonbased SDWE systems,and further guide device optimizations,eventually promoting in extensive practical applications in the future.

Continuous water-water hydrogen bonding network across the rim of carbon nanotubes facilitating water transport for desalination

The development of membranes featuring carbon nanotubes(CNTs)have provided possibilities of next-generation solar desalination technologies.For solar desalination,the microstructures and interactions between the filter membrane and seawater play a crucial role in desalination performance.Understanding the mechanisms of water evaporation and ion rejection in confined pores or channels is necessary to optimize the desalting process.Here,using non-equilibrium molecular dynamics simulations,we found that continuous water-water hydrogen bonding network across the rims of CNTs is the key factor in facilitating water transport through CNTs.With the continuous hydrogen bonding network,the water flux is two times of that without the continuous hydrogen bonding network.In CNT arrays,each CNT transports water molecules and rejects salt ions independently.Based on these observations,using CNT arrays consisted with densely packed thin CNTs is the most advisable strategy for evaporation desalination,possessing high transport flux as well as maintaining high salt rejection.

Hydrophilic carbon nanotube membrane enhanced interfacial evaporation for desalination

Carbon nanotube-based(CNT-based) interfacial evaporation material is one of the most potential materials for solar desalination. Here, we studied the evaporation rate of the CNT-based membranes with different hydrophilic and hydrophobic chemical modified surfaces using molecular dynamic simulations.We found that the hydrogen bonding density among water molecules at the interface is a key factor in enhancing the evaporation rate. For a hydrophilic CNT-based membrane, the strong interactions between the membrane outer surface and the water molecules can destroy the water-water hydrogen bonding interactions at the interface, resulting in the reduction of the hydrogen bonding density, leading to an enhancement effect in evaporation rate. We also found that there is an optimal thickness for evaporation membrane. These findings could provide some theoretical guidance for designing and exploring advanced CNT-based systems with more beneficial performance in water desalination.