Al—Zn—In—Sn牺牲阳极电化学性能研究

本文对Ａｌ－Ｚｎ－Ｉｎ－Ｓｎ牺牲阳极的电化学性能及测试技术进行了探讨，特别对执行ＧＢ４９４８－８５中的一些细节进行了具体而深入的讨论，对腐蚀后试样表面形貌和腐蚀的均匀性问题进行了光学显微镜和扫描电境观察和分析．

In situ observation of cracking and self-healing of solid electrolyte interphases during lithium deposition

The growth of lithium(Li)whiskers is detrimental to Li batteries.However,it remains a challenge to directly track Li whisker growth.Here we report in situ observations of electrochemically induced Li deposition under a CO_(2) atmosphere inside an environmental transmission electron microscope.We find that the morphology of individual Li deposits is strongly influenced by the competing processes of cracking and self-healing of the solid electrolyte interphase(SEI).When cracking overwhelms self-healing,the directional growth of Li whiskers predominates.In contrast,when self-healing dominates over cracking,the isotropic growth of round Li particles prevails.The Li deposition rate and SEI constituent can be tuned to control the Li morphologies.We reveal a new“weak-spot”mode of Li dendrite growth,which is attributed to the operation of the Bardeen-Herring growth mechanism in the whisker’s cross section.This work has implications for the control of Li dendrite growth in Li batteries.

Carbon-coated Fe2O3 hollow sea urchin nanostructures as high-performance anode materials for lithium-ion battery

Fe2O3 has become a promising anode material in lithium-ion batteries (LIBs) in light of its low cost, high theoretical capacity (1007 mA h g^−1) and abundant reserves on the earth. Nevertheless, the practical application of Fe2O3 as the anode material in LIBs is greatly hindered by several severe issues, such as drastic capacity falloff, short cyclic life and huge volume change during the charge/discharge process. To tackle these limitations, carbon-coated Fe2O3 (Fe2O3@MOFC) composites with a hollow sea urchin nanostructure were prepared by an effective and controllable morphology-inherited strategy. Metal-organic framework (MOF)-coated FeOOH (FeOOH@-MIL-100(Fe)) was applied as the precursor and self-sacrificial template. During annealing, the outer MOF layer protected the structure of inner Fe2O3 from collapsing and converted to a carbon coating layer in situ. When applied as anode materials in LIBs, Fe2O3@MOFC composites showed an initial discharge capacity of 1366.9 mA h g^−1 and a capacity preservation of 1551.3 mA h g^−1 after 200 cycles at a current density of 0.1 A g^−1. When increasing the current density to 1 A g^−1, a reversible and high capacity of 1208.6 mA h g^−1 was obtained. The enhanced electrochemical performance was attributed to the MOF-derived carbon coating layers and the unique hollow sea urchin nanostructures. They mitigated the effects of volume expansion, increased the lithium-ion mobility of electrode, and stabilized the as-formed solid electrolyte interphase films.

Confining ultrafine SnS nanoparticles in hollow multichannel carbon nanofibers for boosting potassium storage properties

SnS has been extensively investigated as a potential anode material in potassium-ion batteries (PIBs) for its high theoretical capacity.Nonetheless,it suffers a limited cyclic lifespan owing to its poor electronic conductivity and huge volume expansion.This work proposed a facile approach where SnS nanocrystals are confined in the walls of hollow multichannel carbon nanofibers (denoted SnS@HMCFs) to tackle the issues above.In contrast to previous studies,impregnated ultrafine SnS nanocrystals in HMCFs compactly can increase the SnS loading number per unit area of the carbon matrix.Furthermore,the unique hollow multichannel carbon nanofibers are used as a robust carrier to uniformly distribute the SnS nanocrystals.This can significantly accelerate K;/electron transport,resulting in large specific capacity,outstanding rate performance,and steady cycling property for PIBs.High reversible capacities of 415.5 mAh g^(-1)at0.1 A g^(-1)after 300 cycles and 245.5 mAh g^(-1)at 1 A g^(-1)after 1000 cycles are retained,suggesting great potential of SnS@HMCFs as a negative electrode material for PIBs.Additionally,when the SnS@HMCF anode is assembled with the KVPO_(4)F cathode,the obtained full cell shows a large discharge capacity of165.3 m Ah g^(-1)after 200 cycles at 0.1 A g^(-1).

Interconnected CoS/NC-CNTs network as highperformance anode materials for lithium-ion batteries

Cobalt disulfide(CoS_(2))has been considered a promising anode material for lithium-ion batteries(LIBs)due to its high theoretical capacity of 870 mA h g^(-1).However,its practical applications have been hampered by undesirable cycle life and rate performance due to the volume change and deterioration of electronic conductivity during the dischargecharge process.In this study,an interconnected CoS_(2)/N-doped carbon/carbon nanotube(CoS_(2)/NC-CNTs-700)network was successfully prepared to boost its lithium storage performance,in which small-size CoS_(2)nanoparticles were confined by N-doped carbon and uniformly decorated on the surface of CNTs.N-doped carbon can effectively accommodate the large volume expansion of CoS_(2)nanoparticles.Additionally,the 3D conductive nanostructure design offers adequate electrical/mass transport spacing.Benefiting from this,the CoS_(2)/NCCNTs-700 electrode demonstrates a long cycle life(a residual capacity of 719 mA h g^(-1)after 100 cycles at 0.2 A g^(-1))and outstanding rate performance(335 mA hg^(-1)at 5.0 A g^(-1)).This study broadens the design and application of CoS_(2)and fosters the advances in battery anode research.

Pseudocapacitive sodium storage of Fe1-xS@N-doped carbon for low-temperature operation

Constructing potential anodes for sodium-ion batteries(SIBs)with a wide temperature property has captured enormous interests in recent years.Fe1-xS,a zero-band gap material confirmed by density states calculation,is an ideal electrode for fast energy storage on account of its low cost and high theoretical capacity.Herein,Fe1-xS nanosheet wrapped by nitrogen-doped carbon(Fe1-xS@NC)is engineered through a post-sulfidation strategy using Fe-based metal-organic framework(Fe-MOF)as the precursor.The obtained Fe1-xS@NC agaric-like structure can well shorten the charge diffusion pathway,and significantly enhance the ionic/electronic conductivities and the reaction kinetics.As expected,the Fe1-xS@NC electrode,as a prospective SIB anode,delivers a desirable capacity up to 510.2 mA h g^-1 at a high rate of8000 mA g^-1.Additionally,even operated at low temperatures of 0 and-25°C,high reversible capacities of 387.1 and 223.4 mA h g^-1 can still be obtained at 2000 mA g^-1,respectively,indicating its huge potential use at harsh temperatures.More noticeably,the full battery made by the Fe1-xS@NC anode and Na3 V2(PO4)2 O2 F cathode achieves a remarkable rate capacity(186.8 mA h g^-1 at 2000 m A g^-1)and an impressive cycle performance(183.6 m A h g^-1 after 100 cycles at700 mA g^-1)between 0.3 and 3.8 V.Such excellent electrochemical performance is mainly contributed by its pseudocapacitive-dominated behavior,which brings fast electrode kinetics and robust structural stability to the whole electrode.

A robust,highly reversible,mixed conducting sodium metal anode

Sodium metal anode holds great promise in pursuing high-energy and sustainable rechargeable batteries,but severely suffers from fatal dendrite growth accompanied with huge volume change.Herein,a robust mixed conducting sodium metal anode is designed through incorporating Na SICON-type solid Na-ion conductor into bulk Na.A fast and continuous pathway for simultaneous transportation of electrons and Na+is established throughout the composite anode.The intimate contact between Na-ion conducting phase and Na metallic phase constructs abundant two-phase boundaries for fast redox reactions.Further,the compact configuration of the composite anode substantially protects Na metal from being corroded by liquid organic electrolyte for the minimization of side reactions.Benefiting from the unique configuration,the composite anode shows highly reversible and durable Na plating/stripping behavior.The symmetric cells exhibit ultralong lifespan for over 700 h at 1 mA cm^(-2)with a high capacity of 5 m Ah cm^(-2)and outstanding rate capability up to 8 m A cm^(-2)in the carbonate electrolyte.Full cells with Na_(3)V_(2)(PO_(4))_(3)/C cathode demonstrate impressive cycling stability(capacity decay of 0.012%per cycle)and low charge/discharge polarization as well.This work provides new insights into rational design and development of robust sodium metal anode through an architecture engineering strategy for advanced rechargeable sodium batteries.

SnSe2 nanocrystals coupled with hierarchical porous carbon microspheres for long-life sodium ion battery anode

Tin selenides have been attracting great attention as anode materials for the state-of-the-art rechargeable sodium-ion batteries(SIBs)due to their high theoretical capacity and low cost.However,they deliver unsatisfactory performance in practice,owing to their intrinsically low conductivity,sluggish kinetics and volume expansion during the charge-discharge process.Herein,we demonstrate the synthesis of SnSe2 nanocrystals coupled with hierarchical porous carbon(SnSe2 NCs/C)microspheres for boosting SIBs in terms of capacity,rate ability and durability.The unique structure of SnSe2 NCs/C possesses several advantages,including inhibiting the agglomeration of SnSe2 nanoparticles,relieving the volume expansion,accelerating the diffusion kinetics of electrons/ions,enhancing the contact area between the electrode and electrolyte and improving the structural stability of the composite.As a result,the as-obtained SnSe2 NCs/C microspheres show a high reversible capacity(565 mA h g^-1 after 100 cycles at 100 mA g^-1),excellent rate capability,and long cycling life stability(363 mA h g^-1 at1 A g^-1 after 1000 cycles),which represent the best performances among the reported SIBs based on SnSe2-based anode materials.

Electrolytes enriched by potassium perfluorinated sulfonates for lithium metal batteries

Lithium(Li) metal is widely considered as a promising anode for next-generation lithium metal batteries(LMBs) due to its high theoretical capacity and lowest electrochemical potential. However, the uncontrollable formation of Li dendrites has prevented its practical application. Herein, we propose a kind of multifunctional electrolyte additives(potassium perfluorinated sulfonates) from the multi-factor principle for electrolyte additive molecular design(EDMD) view to suppress the Li dendrite growth. The effects of these additives are revealed through experimental results, molecular dynamics simulations and firstprinciples calculations. Firstly, K^(+)can form an electrostatic shield on the surface of Li anode to prevent the growth of Li dendrites. Secondly, potassium perfluorinated sulfonates can improve the activity of electrolytes as co-conductive salts, and lower the electro-potential of Li nucleation. Thirdly, perfluorinated sulfonate anions not only can change the Li^(+)solvation sheath structure to decrease the desolvation energy barrier and increase the ion migration rate, but also can be partly decomposed to form the superior solid electrolyte interphase(SEI). Benefited from the synergistic effects, an outstanding cycle life over250 h at 1 m A cm^(-2) is achieved in symmetric Li||Li cells. In particular, potassium perfluorinated sulfonate additives(e.g., potassium perfluorohexyl sulfonate, denoted as K+PFHS) can also contribute to the formation of high-quality cathode electrolyte interphase(CEI). As a result, Li||LiNi_(0.6)Mn_(0.2)Co_(0.2)O_(2) full cells exhibit significantly enhanced cycling stability. This multi-factor principle for EDMD offers a unique insight on understanding the electrochemical behavior of ion-type electrolyte additives on both the Li metal anode and high-voltage cathode.

A high-volumetric-capacity bismuth nanosheet/graphene electrode for potassium ion batteries

Potassium ion batteries(PIBs)with high-volumetric energy densities are promising for next-generation low-cost energy storage devices.Metallic bismuth(Bi)with a structure similar to graphite,is a promising anode material for PIBs due to its high theoretical volumetric capacity(3763 mA h cm^−3)and relatively low working potential(−2.93 V vs.standard hydrogen electrode).However,it experiences severe capacity decay caused by a huge volume expansion of Bi when alloying with potassium.This study reports a flexible and free-standing Bi nanosheet(BiNS)/reduced graphene oxide composite membrane with designed porosity close to the expansion ratio of BiNS after charging.The controlled pore structure improves the electron and ion transport during cycling,and strengthens the structural stability of the electrode during potassiation and depotassiation,leading to excellent electrochemical performance for potassium-ion storage.In particular,it delivers a high reversible volumetric capacity of 451 mA h cm^−3 at the current density of 0.5 A g^−1,which is much higher than the previously reported commercial graphite material.

An ultralong-life SnS-based anode through phosphate-induced structural regulation for high-performance sodium ion batteries

As a star representative of transition metal sulfides, Sn S is viewed as a promising anode-material candidate for sodium ion batteries due to its high theoretical capacity and unique layered structure. However,the extremely poor electrical conductivity and severe volume expansion strongly hinder its practical application while achieving a high reversible capacity with long-cyclic stability still remains a grand challenge. Herein, different from the conventional enhancement method of elemental doping, we report a rational strategy to introduce PO_(4)^(3-)into the Sn S layers using phytic acid as the special phosphorus source.Intriguingly, the presence of PO_(4)^(3-)in the form of Sn–O–P covalent bonds can act as a conductive pillar to buffer the volume expansion of Sn S while expanding its interlay spacing to allow more Na+storage, supported by both experimental and theoretical evidences. Profiting from this effect combined with microstructural metrics by loading on high pyridine N-doped reduced graphene oxide, the as-prepared material presented an unprecedented ultra-long cyclic stability even after 10,000 cycles along with high reversible capacity and excellent full-cell performances. The findings herein open up new opportunities for elevating electrochemical performances of metal sulfides and provide inspirations for the fabrication of advanced electrode materials for broad energy use.

Multifunctional V3S4-nanowire/graphene composites for high performance Li-S batteries

Lithium sulfur(Li-S)batteries have been regarded as a promising next-generation energy storage system with high theoretical specific capacity and energy density,but still facing challenges.In order to make Li-S batteries more competitive,combination of trapping sites and electrocatalytic properties for polysulfides is an effective way to improve the battery performance.In this study,we prepare a type of multifunctional V3S4-nanowire/graphene composites(V3S4-G)by uniformly dispersing V3S4 nanowires on the graphene substrate.This structure contributes to the sufficient exposure of multifunctional V3S4 active sites which can anchor polysulfides and accelerate reaction kinetics.Thus,the Li-S batteries based on the multifunctional V3S4-G sulfur cathode deliver a stable cycling performance and good rate capability.Even at sulfur loading of 3 mg cm^−2,the V3S4-G sulfur cathode possesses a low capacity decay rate of 0.186%per cycle at 0.5 C.

Insoluble polyanionic anthraquinones with two strong ionic O–K bonds as stable organic cathodes for pure organic K-ion batteries

A new organic cathode namely potassium 2,6-dihydroxyanthraquinone(AQ26OK,theoretical capacity(CT)=169 mA h g^(-1))is synthesized and fully characterized for Kion batteries.AQ26OK is called polyanionic organic cathode because it has a polyanionic organic skeleton(-2 valent)and two strong ionic K-O bonds.Consequently,the polyanionic AQ26OK is hardly soluble into most organic liquid electrolytes.In half cells(0.3-3.4 V vs.K^(+)/K)using 1 mol L^(-1) KPF6 in dimethoxyethane,AQ26OK delivers a highly stable specific capacity of 201 mA h g^(-1)@50 mA g^(-1) over 450 cycles(4-month test)and realizes~106 mA h g^(-1) for 3200 cycles at 500 mA g^(-1).Using the reduced state(K4TP)of potassium terephthalate(K2TP)as the organic anode,the resulting K4TP Ⅱ AQ26OK organic potassium-ion batteries can display a highly stable average discharge capacity of 135 mA h g^(-1) cathodeover 250 cycles at 100 mA g^(-1) and~47 mA h g^(-1) for 1000 cycles at 500 mA g^(-1) during the working voltage of 0.01-3.1 V.To the best of our knowledge,AQ26OK is among the best stable cathodes reported for K-ion batteries.

A durable P2-type layered oxide cathode with superior low-temperature performance for sodium-ion batteries

To power large-scale energy storage systems,sodium-ion batteries(SIBs)must have not only high-energy density but also high performance under a low-temperature(LT)environment.P2-type manganese oxides with high specific capacity are promising cathode candidates for SIBs,but their LT applications are limitedly explored.We proposed a P2-type Na_(0.67)Ni_(0.1)Co_(0.1)Mn_(0.8)O_(2) material with outstanding LT performance prepared through reasonable structure modulation.The material offers an excellent Na^(+) diffusion coefficient(approximately 10^(−9)-10^(−7.5) cm^(2) s^(−1))at−20℃,a superior LT discharge capacity of 147.4 mA h g^(−1) in the Na half-cell system,and outstanding LT full cell performance(energy density of 358.3 W h kg^(−1)).Various characterisations and density function theory calculations results show that the solid solution reaction and pseudocapacitive feature promote the diffusion and desolvation of Na+from the bulk electrode to interface,finally achieving superior electrochemical performance at LT.