Anion competition for Li^(+)solvated coordination environments in poly(1,3 dioxolane)electrolyte to enable high-voltage lithium metal solid-state batteries

Gel-based polymer electrolytes are limited by the polarity of the residual solvent,which restricts the coupling-breaking behaviour during Li^(+)conduction,resulting in the Li^(+)transport kinetics being greatly affected.Here,we designed anion competitive gel polymer electrolyte(ACPE)by introducing lithium difluoro(oxalato)borate(LiDFOB)anion into the 1,3-dioxolane(DOL)in situ polymerisation system.ACPE enhances the ionic dipole interaction between Li^(+)and the solvent molecules and synergizes with Li^(+)across the solvation site of the polymer ethylene oxide(EO)unit,combination that greatly improves the Li^(+)transport efficiency.As a result,ACPE exhibits 1.12 mS cm^(−1)ionic conductivity and 0.75 Li^(+)transfer number at room temperature.Additionally,this intra-polymer solvation sheath allows preferential desolvation of DFOB−,which contributes to the formation of kinetically stable anion-derived interphase and effectively mitigates side reactions.Our results demonstrate that the assembled Li||NCM622 solid-state battery exhibits lifespan of over 300 cycles with average Coulombic efficiency of 98.8%and capacity retention of 80.3%.This study introduces a novel approach for ion migration and interface design,paving the way for high-safety and high-energy-density batteries.

Recent progress in application of cobalt-based compounds as anode materials for high-performance potassium-ion batteries

Potassium-ion batteries(KIBs)are regarded as one of the most promising replacements for lithium-ion batteries because of their low cost and high performance.Exploring suitable anode materials to stably and effectively store potassium is critical for the development of KIBs.Given their high theoretical specific capacity,cobalt-based compounds have been extensively investigated as an anode material in recent years;however,specific reviews summarizing the research progress in the application of cobaltbased compounds as anode materials for high-performance KIBs are lacking.Consequently,this review systematically summarizes the recent states of cobalt-based anode materials in KIBs starting at the potassium storage mechanism,followed by strategies and applications to improve the electrochemical performance.The current challenges are also discussed,and corresponding prospects are proposed.This work may facilitate the realization of various applications of cobalt-based compound anodes for highperformance rechargeable batteries and is expected to provide some guidance for developing other metal-based compounds for KIBs anodes.

Hierarchically designed MoWSe_(2)/WO_(3)/C anode for fast and efficient Na+storage

Exploring anode materials with high energy and power density is one of the critical milestones in developing sodium-ion batteries/capacitors(SIBs/SICs).Here,the Mo and W-based bimetallic organic framework(Mo-W-MOF)with core-shell structure is first formed by a facile strategy,followed by a selenization and carbonization strategy to finally prepare multileveled Mo WSe_(2)/WO_(3)/C anode materials with core-shell petal like curled nanosheet structure.Between the petal(MoSe_(2))-core(WO_(3))structure,the formation of WSe_(2)flakes by partial selenization on the surface of WO_(3)serves as a heterogeneous connection between MoSe_(2)and WO_(3).The enlarged layer distance(0.677 nm)between MoSe_(2)and WSe_(2)can facilitate the rapid transfer of Na+and electrons.The density functional theory(DFT)calculations verify that the Mo WSe_(2)/WO_(3)/C heterostructure performs excellent metallic properties.Ex-situ X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),and transmission electron microscopy(TEM)confirm the activation process from the initial insertion reaction to the later conversion reaction.Resultantly,when employed as the anode of SIBs,a remarkable capacity of 384.3 mA h g-1after 950 cycles at 10 A g^(-1)is performed.Furthermore,the SICs assembled with commercial activated carbon(AC)as the cathode exhibits a remarkable energy density of 81.86 W h kg^(-1)(at 190 W kg^(-1))and 72.83 W h kg^(-1)(at 3800 W kg^(-1)).The unique structural design and the reaction investigation of the electrode process can provide a reference for the development of transition metal chalcogenides anodes.

Recent advances of high-entropy electrocatalysts for water electrolysis by electrodeposition technology:a short review

Hydrogen is considered as the promising energy carrier to substitute traditional fossil fuel,due to its cleanliness,renewability and high energy density.Water electrolysis is a simple and eonvenient technology for hydrogen production.The efficiency of water electrolysis for hydrogen production is limited by the electrocatalytic performances on hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).The exorbitant Pt-and Ir-/Ru-based electrocatalysts as optimal HER and OER electrocatalysts,respectively,restrict water electrolysis development.Recently,non-precious metal-based high-entropy electrocatalysts have exhibited excellent electrocatalytic activities and long-term stabilities for water electrolysis,as promising precious cataly st candidates.Therefore,the construction of the high-entropy electroc atalysts is vital to water electrolysis industry.Electrodeposition technology is an efficient method for the preparation of high-entropy electrocatalysts due to its simple,fast,energy-saving and environmental-friendly advantages.Multi-component co-precipitation facilely occurs during the electroredox in electrodeposition processes.High-entropy alloys,oxides,(oxy)hydroxides,phosphides and phosphorus sulfide oxides have been successfully prepared by galvanostatic,potentiostatic electrodeposition,cyclic voltammetry,pulse,nanodroplet-mediated and cathodic plasma electrodeposition techniques.Hence,introduction of the development of high-entropy electrocatalysts synthesized by electrodeposition technology is significant to researchers and industries.Challenges and outlooks are also concluded to boost the industrial application of electrodeposition in water electrolysis and other energy conversion areas.

In situ regulating intimately connected heterostructure by decomposition of solid solution oxides toward high-efficient water oxidation

Heterogeneous interfaces produced by interdomain interactions on a nanoscale performs a crucial role in boosting the properties of an electrocatalyst toward oxygen evolution reaction(OER)process.Herein,a series of dual-phase electrodes with intimately connected heterointerfaces are prepared by in situ decomposing solid solution oxide of Ni_(x)Co_(y)Fe_(100-x-y)O,which grew on Ni foam massively via an ultrafast combustion approach.Particularly,with high-reaction kinetics caused by the reduction treatment at 450℃,the less electronegative Fe and Co are more oxyphilic than Ni,which facilitated their co-exsolution and formation of CoFe_2O_4/NiO oxide with enriched oxygen vacancies.Benefiting from the nanoporous framework,heterojunction structure,and oxygen defects,the self-supporting electrodes present rapid charge/mass transmission and provide abundant active sites for OER.The optimized sample(R-SNCF4.5)shows low overpotentials of 226 and 324 mV at 10 and100 mA·cm^(-2),a small Tafel slope(46.7 mV·dec^(-1)),and excellent stability.The assembled R-SNCF4.5//Pt/C/NF electrolyzer demonstrates continuous electrolysis over 50 h at a current density of 10 mA·cm^(-2),under 1.51 V.Density functional theory(DFT)calculations verify that the strong electronic modulation plays a critical part in the CoFe_2O_4/NiO hybrid by lowering the energy barriers for the ratedetermining steps,and Fe sites are the most active OER sites.

Review on Intrinsic Electrocatalytic Activity of Transition Metal Nitrides on HER

Hydrogen energy is considered as an ideal energy with the advantages of green,sustainability,and high energy density,and water splitting is one of the efficient strategies for green hydrogen without carbon emission.As for cathodic hydrogen evolution reaction(HER),besides the Pt-based electrocatalysts with excellent electrocatalytic activities on HER,transition metal nitrides(TMNs)as cheap and facile-prepared electrocatalysts have shown remarkable electrocatalytic activities.Incorporation of N atom in metal interstitial lattice results in the unique structure of TMN with high electronic conductivity,strong chemical stability,and d-band contraction.Although the intrinsic electrocatalytic activities of TMNs are mostly lower than those of Pt,it also attracted much attention to the development of TMN with higher intrinsic activity by electronic structure modulation.Here,we review the recent improvement strategies for the intrinsic electrocatalytic activities of TMN catalysts on HER by electronic structure modulation,such as facet,alloying,doping,vacancy,heterostructure,and hybridization.Some important breakthroughs of TMNs have been made;however,the scale application of TMNs with high activity in commercial water electrolyzer is urgent to explore.The future development of TMNs is proposed to focus on developing facile synthesis methods,elucidating regulation mechanism and catalytic mechanism,and enhancing activity and stability.

Synergistically enabling the interface stability of lithium metal batteries with soft ionic gel and garnet-type Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)ceramic filler

Lithium metal batteries based on solid electrolytes are considered as promising candidates with high energy density and safety.However,the weak solid-solid contact between electrolyte and electrode can easily lead to interface instability and lithium ions discontinuous migration,which seriously reduces the electrochemical performance of the battery.Herein,we construct a soft gel interfacial layer to improve the stability of the solid-solid interface between electrolyte and electrode by means of polyester-based monomers and imidazole-based ionic liquids.Based on this,garnet-type Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)particles as inorganic ceramic filler were introduced in the layer to obtain composite electrolytes with high ionic conductivity(up to 1.1×10^(-3)S/cm at 25℃).As a result,the assembled lithium symmetric battery of Li|THCE-15%LLZTO|Li suggests excellent cycling stability with 700 h at 0.1 mA/cm^(2)at 50℃,and the lithium metal batteries of LFP|THCE-15%LLZTO|Li delivers high initial discharge capacity of 128.2 mA·h/g with capacity retain of 75.48%after 150 cycles at 2 C.This work paves a new route to build safe and stable lithium metal batteries with synergistic introduction of composite electrolytes between electrolyte and electrode using soft gel interfacial layer and inorganic filler.

Amorphous high-entropy phosphoxides for efficient overall alkaline water/seawater splitting

Designing and synthesizing cost-effective bifunctional catalysts for overall alkaline water/seawater splitting is still a huge challenge for hydrogen production.Herein,Co/Ni/Fe/Mn based-amorphous high-entropy phosphoxide self-standing electrode(CNFMPO)is synthesized by the facile and fast electrodeposition method.CNFMPO exhibits excellent bifunctional electrocatalytic performances on alkaline water/seawater electrolysis.The hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)overpotentials of CNFMPO in alkaline water/seawater are as low as 43/73 and 252/282 mV to reach a current density of 10 mA cm^(-2),respectively.Additionally,two-electrode electrolyzers with CNFMPO||CNFMPO successfully achieve the current density of 10 mA cm^(-2) at low voltages of 1.54 and 1.56 V for overall alkaline water/seawater splitting,respectively.CNFMPO exhibits satisfactory long-term stability on overall alkaline water/seawater splitting for the surface reconstruction into active metal hydroxide/(oxy)hydroxide,phosphite,and phosphate.Moreover,no hypochlorite is detected during seawater electrolysis for the beneficial chlorite oxidation inhibition of the reconstructed phosphite and phosphate.The excellent catalytic performances of CNFMPO are due to the unique amorphous structure,multi-component synergistic effect,beneficial electronic structure modulation,and surface reconstruction during the catalytic reaction process.Therefore,CNFMPO has shown potential promotion to the development of the water/seawater splitting industry as a promising substituent for noble-metal electrocatalysts.This work provides new insights into the design of efficient bifunctional catalysts for overall water/seawater splitting.

Regulating Oxygen Vacancy Defects in Heterogeneous NiO-CeO_(2)−δ Hollow Multi-shelled Structure for Boosting Oxygen Evolution Reaction

CeO_(2) with excellent oxygen storage-exchange capacity and NiO with excellent surface activity were used to construct a heterogeneous NiO-CeO_(2)−δhollow multi-shelled structure(HoMS)by spray drying.It turned out that as the proportion of CeO_(2) increases,the overpotential and Tafel slope of NiO-CeO_(2)−δHoMSs first decreased and then increased.This is mainly because the construction of the NiO-CeO_(2)−δHoMSs not only increases the specific surface area,but also introduces oxygen vacancy defects,thus improving the interface charge transfer capability of the materials and further improving the oxygen evolution reaction(OER)performance.However,the increase of the calcination temperature will induce the decay of the OER performance of NiO-CeO_(2)−δHoMSs,which is mainly due to the decrease of the specific surface area,the reduction of oxygen vacancy defects,and the weakening of interface charge transfer capability.Furthermore,a series of heterogeneous composite HoMSs,such as Ni/Co,Mo/Ni,Al/Ni and Fe/Ni oxides was successfully constructed by spray drying,which enriched the diversity of HoMSs.

半离子C-F键在钾离子电池碳负极中诱导快速离子储存和电子转移

氟(F)杂原子功能化的碳负极可以形成更多的缺陷位点,从而有效提高钾的存储容量.然而,提高电化学性能的机制尚不清楚,尤其是对何种C-F键深入影响钾储存性能仍缺乏基本认识.本文报道了一系列F掺杂的碳,并证明了C-F是半离子键而不是离子键;碳化温度对缺陷程度有显著影响.并且,高比例半离子C-F键诱导的丰富缺陷可以作为活性位点来吸附大量与电容行为相关的钾离子,不仅有利于长循环寿命,而且提升了在高电流密度下的倍率容量.密度泛函理论计算证实半离子C-F键的存在可以提高碳基体对钾离子的吸附能力并同时提高电子电导率,有利于高容量和倍率.此外,通过耦合半离子C-F键和吡啶N键,钾吸附能和电导率被进一步提升,这使得半电池实现了优异的容量(245.2 mA h g^(-1))和倍率,并且组装的全电池具有高能量密度(143.9 W h kg^(-1)).

A two-step strategy for constructing stable gel polymer electrolyte interfaces for long-life cycle lithium metal batteries

Due to the high reactivity between the lithium metal and traditional organic liquid electrolyte,the reaction of lithium metal electrode is usually uneven and there are also unexpected side reactions.Therefore,construction of a stable solid electrolyte interface(SEI)is highly essential to improve the performance of lithium metal anode.Herein,a sandwich-like gel polymer electrolyte(GPE)is accurately prepared by in-situ polymerization of Polyacrylonitrile(PAN)nanofiber membrane with trihydroxymethylpropyl trimethylacrylate(TMPTMA)and 1,6-hexanediol diacrylate(HDDA).The resulting GPE with a tightly cross-linked gel skeleton exhibits high ionic conductivity and electrochemical window of 5.6 V versus Li/Li^(+).In particular,the pretreatment of Li metal anode can improve the interfacial wettability,and the synergy of the chemically pretreated Li metal anode surface and the GPE can electrochemically in situ generate SEI with compositionally stable and fluorine-rich inorganic components.Owing to these unique advantages,the interfacial compatibility between the GPE and lithium metal is greatly improved.Meanwhile,the formed SEI can inhibit the formation of lithium dendrites,and decomposition of GPE would be alleviated.The assembled Li-FEC|GPE|LiFePO_(4) full cell shows a high initial discharge capacity of 157.1 mA h g^(-1),and maintains a capacity retention of 92.3%after 100 cycles at 0.2C.

Research and strategies for efficient electrocatalysts towards anodic oxygen evolution reaction in seawater electrolysis system

Seawater electrolysis is one most promising development directions for future hydrogen energy.How-ever,big challenges of active site poisoning,chloride oxidation(ClOR),and chloride corrosion on anode electrocatalysts,seriously impede seawater electrolysis development.Therefore,developing efficient an-odic oxygen evolution reaction(OER)electrocatalysts is an urgent task for seawater electrolysis.The ad-vanced strategies of improving OER kinetics,lowering ClOR kinetics,strengthening corrosion resistance,and recombining multifunction are summarized and analyzed to help researchers quickly grasp the re-cent progress on seawater oxidation.The outlooks for future research are put forward.The future research directions are proposed as internal and external cultivation,giving full play to the physicochemical prop-erties of electrocatalysts,making sense of structure evolution and OER mechanism,and elucidating the electrical double layer of electrocatalysts.A lot of room for scalable application of seawater electrolysis calls for persistent effort and devotion of related researchers to boost seawater electrolysis development and universal hydrogen energy application.