Rational screening of metal coating on Zn anode for ultrahigh-cumulative-capacity aqueous zinc metal batteries

Aqueous zinc metal batteries feature intrinsic safety,but suffer from severe dendrite growth and water-derived side reactions.Many metal coatings have been explored for stabilizing Zn metal anode via a trialand-error approach.Here,we propose an exercisable way to screen the potential metal coating on Zn anodes in view of de-polarization effect and dendrite-suppressing ability theoretically.As an output of this screening,cadmium(Cd) metal is checked experimentally.Therefore,symmetric ZnllZn cells using Cd coated Zn(Zn@Cd) exhibit an ultra-long cycle life of 3500 h(nearly 5 months) at a high current density of 10 mA cm^(-2),achieving a record-high cumulative capacity(35 A h cm^(-2)) compared to the previous reports.The full cells of Zn@Cd‖MnO_(2) display a markedly improved cycling performance under harsh conditions including a limited Zn supply(N/P ratio=1.7) and a high areal capacity(3.5 mA h cm^(-2)).The significance of this work lies in not only the first report of Cd coating for stabilizing Zn metal anode,but also a feasible way to screen the promising metal materials for other metal anodes.

A general synthesis of inorganic nanotubes as high-rate anode materials of sodium ion batteries

Ino rganic tubular materials have an exceptionally wide range of applications,yet developing a simple and universal method to controllably synthesize them remains challenging.In this work,we report a vaporphase-etching hard-template method that can directly fabricate tubes on various thermally stable oxide and sulfide materials.This synthesis method features the introduction of a vapor-phase-etching process to greatly simplify the steps involved in preparing tubular materials and avoids complicated postprocessing procedures.Furthermore,the in-situ heating transmission electron microscopy(TEM)technique is used to observe the dynamic formation process of TiO_(2-x) tubes,indicating that the removal process of the Sb2S3 templates first experienced the Rayleigh instability,then vapor-phase-etching process.When used as an anode for sodium ion batteries,the TiO_(2-x) tube exhibits excellent rate performance of134.6 mA h g^(-1) at the high current density of 10 A g^(-1) and long-term cycling over 7000 cycles.Moreover,the full cell demonstrates excellent cycling performance with capacity retention of 98%after 1000 cycles,indicating that it is a promising anode material for batteries.This method can be expanded to the design and synthesis of other thermally-stable tubular materials such as ZnS,MoS_(2),and SiO_(2).

Phase-separated bimetal enhanced sodium storage:Dimer-like Sn-Bi@C heterostructures with high capacity and long cycle life

Phase boundaries facilitate the charge transportation and alleviate the intrinsic stress upon cycles.Therefore,how to achieve regular phase boundaries is very attractive.Herein,dimer-like Sn-Bi@C nanostructures,where is a well-defined phase boundary between Sn and Bi,have been prepared by a two-step process for the first time.The phase boundary not only provides additional and fast transportation for Na+,but also mitigates the structure stress/strain upon cycling.Therefore,Sn-Bi@C exhibits a high capacity(472.1 m A h g^(-1)at 2 A g^(-1)for 200 cycles),an ultra-long cyclic life(355.6 mA h g^(-1)at 5 A g^(-1)for 4500cycles)and an excellent rate performance(372 mA h g^(-1)at 10 A g^(-1))for sodium storage,much higher than those of Sn@C,Bi@C,and Sn@C+Bi@C.Notably,the full cells of Sn-Bi@C//Na_(3)V_(2)(PO_(4))_(3)/rGO(SnBi@C//NVP/rGO)demonstrate impressive performance(323 mA h g^(-1)at 2 A g^(-1)for 300 cycles).The underlying mechanism for such an excellent performance is elucidated by in-situ X-ray diffraction,exsitu scanning electron microscopy/high-resolution transmission electron microscopy and atomic force microscopy,revealing the good electrode stability and improved mechanical properties of Sn-Bi@C.The synthetic method is extended to dimer-like Sn-Pb@C and Sn-Ag@C heterostructures,which also exhibit the good cycle stability for sodium storage.

Electrolyte additive enhances the electrochemical performance of Cu for rechargeable Cu//Zn batteries

Cu-based cathodes in aqueous batteries become very attractive in view of high theoretical capacity,moderate operation voltage and rich reserves of raw materials.However,their applications are obstructed by serious side reactions.The side reaction mainly arises from the spontaneous formation of Cu_(2)O,which occupies the electrode surface and lowers the reaction reversibility.Here,Na_(2)EDTA is introduced to address these issues.Both experimental results and theoretical calculations indicate that the Na_(2)EDTA reshapes the solvation structure of Cu^(2+)and modifies the electrode/electrolyte interface.Therefore,the redox potential of Cu^(2+)/Cu_(2)O is reduced and the surface of Cu is protected from H2O,thereby inhibiting the formation of Cu_(2)O.Meanwhile,the change in the solvation structure reduces the electrostatic repulsion between Cu^(2+)and the cathode,leading to high local concentration and benefiting uniform deposition.The results shed light on the applications of rechargeable Cu-based batteries.

Novel Bilayer-Shelled N,O-Doped Hollow Porous Carbon Microspheres as High Performance Anode for Potassium-Ion Hybrid Capacitors

With the advantages of high energy/power density,long cycling life and low cost,dual-carbon potassium ion hybrid capacitors(PIHCs)have great potential in the field of energy storage.Here,a novel bilayer-shelled N,O-doped hollow porous carbon microspheres(NOHPC)anode has been prepared by a self-template method,which is consisted of a dense thin shell and a hollow porous spherical core.Excitingly,the NOHPC anode possesses a high K-storage capacity of 325.9 mA h g^(−1)at 0.1 A g^(−1)and a capacity of 201.1 mAh g^(−1)at 5 A g^(−1)after 6000 cycles.In combination with ex situ characterizations and density functional theory calculations,the high reversible capacity has been demonstrated to be attributed to the co-doping of N/O heteroatoms and porous structure improved K+adsorption and intercalation capabilities,and the stable long-cycling performance originating from the bilayer-shelled hollow porous carbon sphere structure.Meanwhile,the hollow porous activated carbon microspheres(HPAC)cathode with a high specific surface area(1472.65 m^(2)g^(−1))deriving from etching NOHPC with KOH,contributing to a high electrochemical adsorption capacity of 71.2 mAh g^(−1)at 1 A g^(−1).Notably,the NOHPC//HPAC PIHC delivers a high energy density of 90.1 Wh kg^(−1)at a power density of 939.6 W kg^(−1)after 6000 consecutive charge-discharge cycles.

Cu_(3)P nanoparticles confined in nitrogen/phosphorus dual-doped porous carbon nanosheets for efficient potassium storage

Immobilizing primary electroactive nanomaterials in porous carbon matrix is an effective approach for boosting the electrochemical performance of potassium-ion batteries (PIBs) because of the synergy among functional components. Herein, an integrated hybrid architecture composed of ultrathin Cu_(3)P nanoparticles (~20 nm) confined in porous carbon nanosheets (Cu_(3)P⊂NPCSs) as a new anode material for PIBs is synthesized through a rational self-designed self-templating strategy. Benefiting from the unique structural advantages including more active heterointerfacial sites, intimate and stable electrical contact, effectively relieved volume change, and rapid K^(+) ion migration, the Cu_(3)P⊂NPCSs indicate excellent potassium-storage performance involving high reversible capacity, exceptional rate capability, and cycling stability. Moreover, the strong adsorption of K^(+) ions and fast potassium-ion reaction kinetics in Cu_(3)P⊂NPCSs is verified by the theoretical calculation investigation. Noted, the intercalation mechanism of Cu_(3)P to store potassium ions is, for the first time, clearly confirmed during the electrochemical process by a series of advanced characterization techniques.

Nitrogen and fluorine co-doped TiO_(2)/carbon microspheres for advanced anodes in sodium-ion batteries: High volumetric capacity, superior power density and large areal capacity

Fast charging and high volumetric capacity are two of the critical demands for sodium-ion batteries(SIBs).Although nanostructured materials achieve outstanding rate performance,they suffer from low tap density and small volumetric capacity.Therefore,how to realize large volumetric capacity and high tap density simultaneously is very challenging.Here,N/F co-doped TiO_(2)/carbon microspheres(NF- TiO_(2)/C)are synthesized to achieve both of them.Theoretical calculations reveal that N and F co-doping increases the contents of oxygen vacancies and narrows the bandgaps of TiO_(2) and C,improving the electronic conductivity of NF- TiO_(2)/C.Furthermore,NF- TiO_(2)/C exhibits the high binding energy and low diffusion energy barrier of Na+,significantly facilitating Na+storage and Na+diffusion.Therefore,NF- TiO_(2)/C offers a high tap density(1.51 g cm^(-3)),an outstanding rate performance(125.9 mAh g^(-1) at 100 C),a large volumetric capacity(190 mAh cm^(-3) at 100 C),a high areal capacity(4.8 mAh cm^(-2))and an ultra-long cycling performance(80.2%after 10,000 cycles at 10 C)simultaneously.In addition,NF- TiO_(2)/C||Na_(3)V_(2)(PO_(4))_(3) full cells achieve an ultrahigh power density of 25.2 kW kg^(-1).These results indicate the great promise of NF- TiO_(2)/C as a high-volumetric-capacity and high-power-density anode material of SIBs.

Preparation of polypyrrole-coated CuFe_2O_4 and their improved electrochemical performance as lithium-ion anodes

CuFe_2O_4 network,prepared via the electrostatic spray deposition technique,with high reversible capacity and long cycle lifetime for lithium ion battery anode material has been reported.The reversible capacity can be further enhanced by coating high electronic conductive polypyrrole(PPy).At the current density of 100mA·g^(-1).Li/CuFe_2O_4 electrode delivers a reversible capacity of 842.9 mAh·g^(-1) while the reversible capacity of Li/PPy-coated CuFe_2O_4 electrode increases up to 1106.7 mAh-g~'.A high capacity of 640.7 mAhg"1 for the Li/PPy-coated CuFe_2O_4electrode is maintained in contrast of 398.9 mAh·g^(-1) for CuFe_2O_4 electrode after 60 cycles,which demonstrates good electrochemical performance of the composite due to the increase of electronic conductivity.The electrochemical impedance spectroscopy(EIS) further reveals that the Li/PPy-coated CuFe_2O_4 electrode has a lower charge transfer resistance than the Li/CuFe2C>4 electrode.

Superior surface electron energy level endows WP_(2) nanowire arrays with N_(2) fixation functions

Nitrogen reduction reaction(NRR)under ambient conditions is always a long-standing challenge in science,due to the extreme difficulty in breaking the strong N≡N triple bond.The key to resolving this issue undoubtedly lies in searching superior catalysts to efficiently activate and hydrogenate the stable nitrogen molecules.We herein evaluate the feasibility of WP_(2) for N2 activation and reduction,and first demonstrate WP_(2) with an impressive ammonia yield rate of 7.13 lg h^(-1)cm^(-2),representing a promising W-based catalyst for NRR.DFT analysis further reveals that the NRR catalysis on WP_(2) proceeds in a distal reaction pathway,and the exceptional NRR activity is originated from superior surface electron energy level matching between WP_(2) and NRR potential which facilitates the interfacial proton-coupled electron transfer dynamics.The successfully unraveling the intrinsic catalytic mechanism of WP_(2) for NRR could offer a powerful platform to manipulate the NRR activity by tuning the electron energy levels.

Understanding electrolyte salt chemistry for advanced potassium storage performances of transition-metal sulfides

Molybdenum disulfide/carbon nanotubes assembled by ultrathin nanosheets are synthesized to illustrate the electrolyte salt chemistry via potassium bis-(fluorosulfonyl)imide(KFSI)versus potassium hexafluorophosphate(KPF6).Compared to the case of KPF6,the electrochemical performances using KFSI as the electrolyte salt are greatly improved:~275 mAh g^(−1) after 15,000 cycles at 1 A g^(−1),or~172 mAh g^(−1) even at 40 A g^(−1).These results represent one of the best performances for the reported anode materials.The enhanced performances could be attributed to the FSI-induced changes in the solvate structures,that is,a large solvation energy,a high lowest unoccupied mole cular orbital,and a small bonding dissociation energy of S-F.In this case,a uniform and robust solid-electrolyte interphase(SEI)is produced,improving the mechanical properties and the interface integrity.Then,the uncontrollable fracture and repeated growth of SEI,which always lead to the dissolution of sulfur species and the blockage of charge transfer in the case of KPF6,are well inhibited.This similar enhancement works for other sulfides by KFSI,demonstrating the general importance of this electrolyte salt chemistry.

The Growth of Micro-and Nanocrystals

Based on the given reaction condition and medium,the growth of micro-and nanocrystals can be divided into four types,growth in solution at normal pressure,hydrothermal growth,solvothermal growth,and molten-salt growth.When the water or organic solvent as the reaction medium,surfactant,such as sodium dodecyl benzene sulfonate,can be added to regulate

In-situ formation of hierarchical solid-electrolyte interphase for ultra-long cycling of aqueous zinc-ion batteries

Aqueous rechargeable zinc ion batteries have received widespread attention due to their high energy density and low cost.However,zinc metal anodes face fatal dendrite growth and detrimental side reactions,which affect the cycle stability and practical application of zinc ion batteries.Here,an in-situ formed hierarchical solid-electrolyte interphase composed of InF3,In,and ZnF2 layers with outside-in orientation on the Zn anode(denoted as Zn@InF3)is developed by a sample InF3 coating.The inner ultrathin ZnF2 interface between Zn anode and InF3 layer formed by the spontaneous galvanic replacement reaction between InF3 and Zn,is conductive to achieving uniform Zn deposition and inhibits the growth of Zinc dendrites due to the high electrical resistivity and Zn2+conductivity.Meanwhile,the middle uniformly generated metallic In and outside InF3 layers functioning as corrosion inhibitor suppressing the side reaction due to the waterproof surfaces,good chemical inactivity,and high hydrogen evolution overpotential.Besides,the as-prepared zinc anode enables dendrite-free Zn plating/stripping for more than 6,000 h at nearly 100%coulombic efficiency(CE).Furthermore,coupled with the MnO2 cathode,the full battery exhibits the long cycle of up to 1,000 cycles with a low negative-to-positive electrode capacity(N/P)ratio of 2.8.

High ionic conductive protection layer on Zn metal anode for enhanced aqueous zinc-ion batteries

Aqueous zinc-ion batteries(ZIBs)has been regarded as a promising energy storage system for large-scale application due to the advantages of low cost and high safety.However,the growth of Zn dendrite,hydrogen evolution and passivation issues induce the poor electrochemical performance of ZIBs.Herein,a Na_(3)Zr_(2)Si_(2)PO_(12)(NZSP)protection layer with high ionic conductivity of 2.94 m S/cm on Zn metal anode was fabricated by drop casting approach.The protection layer prevents Zn dendrites formation,hydrogen evolution as well as passivation,and facilitates a fast Zn~(2+)transport.As a result,the symmetric cells based on NZSP-coated Zn show a stable cycling over 1360 h at 0.5 m A/cm^(2)with 0.5 m Ah/cm^(2) and 1000 h even at a high current density of 5 m A/cm^(2) with 2 m Ah/cm^(2).Moreover,the full cells combined with V_(2)O_(5)-based cathode displays high capacities and high rate capability.This work offers a facile and effective approach to stabilizing Zn metal anode for enhanced ZIBs.

在NaCl非水离子液体中制备类石墨烯状氮硫共掺杂生物质碳材料来提高锂硫电池的动力学研究（英文）

本论文通过结构设计利用简单方法成功制备了一种二维N,S共掺杂类石墨烯纳米片复合结构,即利用NaCl非水离子液体的剥离作用使生物质剥离得到二维片层类石墨烯结构.这种新的非水离子液体剥离技术较其他的碳材料剥离技术具有环境友好性、低成本、安全无毒性等优势,有利于实现量化制备锂硫电池电极材料.该材料采用大自然中广泛存在的紫菜作为原料,其内部富含的氨基酸为原位掺杂N,S元素提供了可能性.二维结构的纳米片能够提供有效的导电性和电解液浸润性的网络结构,同时还能够有效地降低电池在充放电循环过程中导致的体积膨胀效应,最终实现一种高机械性能、优异电化学活性的电极在锂硫电池储能领域中的应用.

Carbon-coated mesoporous Co9S8 nanoparticles on reduced graphene oxide as a long-life and high-rate anode material for potassium-ion batteries

Carbon-coated mesoporous Co9S8 nanoparticles supported on reduced graphene oxide(rGO)are successfully synthesized by a simple process.This composite makes full use of the protection of the carbon layer on the surface,the good conductivity and three-dimensional(3D)structure of rGO,the mesoporous structure and nanoscale size of Co9S8,thereby presenting the excellent electrochemical performances in potassium-ion batteries,407.9 mAh·g^−1 after 100 cycles at 0.2 A·g^−1 and 215.1 mAh·g^−1 at 5 A·g^−1 in rate performances.After 1,200 cycles at 1.0 A·g^−1,this composite still remains a capacity of 210.8 mAh·g^−1.The redox reactions for potassium storage are revealed by ex-situ transmission electron microscope(TEM)/high-resolution TEM(HRTEM)images,selected area electron diffraction(SAED)patterns and X-ray photoelectron spectroscopy(XPS)spectra.The application of this composite as the host of sulfur for Li-S batteries is also explored.It sustains a capacity of 431.8 mAh·g^−1 after 800 cycles at 3 C,leading to a degradation of 0.052%per cycle.These results confirm the wide applications of this composite for electrochemical energy storage.

Simple synthesis of a porous Sb/Sb2O3 nanocomposite for a high-capacity anode material in Na-ion batteries

高能力的阳极材料为钠离子电池是高度合乎需要的。这里，多孔的 Sb/Sb 2 O 3 nanocomposite 被 Sb nanocrystals 的温和氧化成功地在空中综合。在里面合成， Sb 贡献好电导率和 Sb 2 O 3 改进骑车的稳定性，特别地在 0.02-1.5 V 的电压窗户以内。它在 540 mAh 的一个可逆能力留下 ??? ′

Co0.85Se hollow spheres constructed of ultrathin 2D mesoporous nanosheets as a novel bifunctional-electrode for supercapacitor and water splitting

Hollow spheres of Co0.85Se con structed by two-dime nsional(2D)mesoporous ultrathi nnanosheets were synthesized via simple and costeffective approach.Their bifunctional electrocatalytic-supercapacitive properties were obtained simultaneously due to synergistic effects betweenmacroscopic morphological features and microscopic atomic/electronic structure of Co0.85Se.The as-synthesized hollow spheres of Co0.85Sethat are con structed by 2D mesoporous ultrathin nanosheets exhibit in spiring electrochemical performance for supercapacitor,presenting maximum energy density at high power density(54.66 Wh·kg^-1 at 1.6 kW·kg^-1)and long cycle stability(88%retention after 8,000 cycles).Atthe same time,the hollow spheres of Co0.85Se constructed by 2D mesoporous ultrathin nanosheets display excellent catalytic performaneefor oxygen evolution reaction(OER)due to special structure,high surface area and mesoporous nature of sheets,which achieve lowoverpotential(290 mV at 10 mA·g^-1)and low Tafel slope(81 mV·dec^-1)for Iong-term operation(only 7.8%decay in current density after 9 h).It could be envisioned that the proposed simple approach will pave a new way to synthesize other metal chalcoge nides for energy conversionand storage technology.

Defect engineering on carbon black for accelerated Li-S chemistry

Rationally designing sulfur hosts with the functions of confining lithium polysulfides(LiPSs)and promoting sulfur reaction kinetics is critically important to the real implementation of lithium-sulfur(Li-S)batteries.Herein,the defect-rich carbon black(CB)as sulfur host was successfully constructed through a rationally regulated defect engineering.Thus-obtained defect-rich CB can act as an active electrocatalyst to enable the sulfur redox reaction kinetics,which could be regarded as effective inhibitor to alleviate the LiPS shuttle.As expected,the cathode consisting of sulfur and defect-rich CB presents a high rate capacity of 783.8 mA·h·g^−1 at 4 C and a low capacity decay of only 0.07% per cycle at 2 C over 500 cycles,showing favorable electrochemical performances.The strategy in this investigation paves a promising way to the design of active electrocatalysts for realizing commercially viable Li-S batteries.

Synthesis of carbon nanotubes-supported porous silicon microparticles in low-temperature molten salt for highperformance Li-ion battery anodes

Silicon-based materials has attracted attention as a promising candidate for lithium-ion batteries(LIBs)with high energy density.However,severe volume variation,pulverization,and poor conductivity hindered the development of Si based materials.In this study,porous Si microparticles supported by carbon nanotubes(p-Si/CNT)are fabricated through simple molten salt assisted dealloying process at low temperature followed by acid treatment.The ZnCl2 molten salt not only provides the liquid environment to enhance the reaction,but also participates the dealloying process and works as template for porous structure when removes by acid treatment.Additionally,distribution of defect sites in CNTs also increases after molten salt process.Density function theory(DFT)calculations further prove the defects could improve the adsorption of Li+.The participation of CNTs can also contribute to the reaction kinetics and retain the integrity of the electrode.As expected,the p-Si/CNT anode manifests enhanced lithium-storage performance in terms of superior cycling stability and good rate capability.The p-Si/CNT//LiCoO_(2) full cell assembly further demonstrates its potential as a prospective anode for high-performance LIBs.

2D interspace confined growth of ultrathin MoS_(2)-intercalated graphite hetero-layers for high-rate Li/K storage

Herein,a two-dimensional(2D)interspace-confined synthetic strategy is developed for producing MoS_(2)intercalated graphite(G-MoS_(2))hetero-layers composite through sulfuring the pre-synthesized stage-1 MoCI5-graphite intercalation compound(M0 CI5-GIC).The in situ grown MoS_(2)nanosheets(3-7 layers)are evenly encapsulated in graphite layers with intimate interface thus forming layer-by-layer MoS_(2)-intercalated graphite composite.In this structure,the unique merits of MoS_(2)and graphite components are integrated,such as high capacity contribution of MoS_(2)and the flexibility of graphite layers.Besides,the tight interfacial interaction between hetero-layers optimizes the potential of conductive graphite layers as matrix for MoS_(2).As a result,the G-MoS_(2)exhibits a high reversible Li+storage of 344 mAh·g^(-1)even at 10 A·g^(-1)and a capacity of 539.9 mAh·g^(-1)after 1,500 cycles at 5 A·g^(-1).As for potassium ion battery,G-MoS_(2)delivers a reversible capacity of 377.0 mAh·g^(-1)at 0.1 A·g^(-1)and 141.2 mAh·g^(-1)even at 2 A·g^(-1).Detailed experiments and density functional theory calculation demonstrate the existence of hetero-layers enhances the diffusion rates of Li^(+)and K^(+).This graphite interspace-confined synthetic methodology would provide new ideas for preparing function-integrated materials in energy storage and conversion,catalysis or other fields.