查看更多>>摘要：The sluggish kinetics of complicated multiphase conversions and the severe shuttling effect of lithium polysulfides(LiPSs)significantly hinder the applications of Li-S battery,which is one of the most promising candidates for the next-generation energy storage system.Herein,a bifunctional electrocatalyst,indium phthalocyanine self-assembled with carbon nanotubes(InPc@CNT)composite material,is proposed to promote the conversion kinetics of both reduction and oxidation processes,demonstrating a bidirectional catalytic effect on both nucleation and dissolution of Li2S species.The theoretical calculation shows that the unique electronic configuration of InPc@CNT is conducive to trapping soluble polysulfides in the reduction process,as well as the modulation of electron transfer dynamics also endows the dissolution of Li2S in the oxidation reaction,which will accelerate the effectiveness of catalytic conversion and facilitate sulfur utilization.Moreover,the InPc@CNT modified separator displays lower overpotential for polysulfide transformation,alleviating polarization of electrode during cycling.The integrated spectroscopy analysis,HRTEM,and electrochemical study reveal that the InPc@CNT acts as an efficient multifunctional catalytic center to satisfy the requirements of accelerating charging and discharging processes.Therefore,the Li-S battery with InPc@CNT-modified separator obtains a discharge-specific capacity of 1415 mAh g-1 at a high rate of 0.5 C.Additionally,the 2 Ah Li-S pouch cells deliver 315 Wh kg-1 and achieved 80％capacity retention after 50 cycles at 0.1 C with a high sulfur loading of 10 mg cm-2.Our study provides a practical method to introduce bifunctional electrocatalysts for boosting the electrochemical properties of Li-S batteries.
查看更多>>摘要：Sodium-ion batteries(SIBs)have rapidly risen to the forefront of energy storage systems as a promising supplementary for Lithium-ion batteries(LIBs).Na3V2(PO4)2F3(NVPF)as a common cathode of SIBs,features the merits of high operating voltage,small volume change and favorable specific energy density.However,it suffers from poor cycling stability and rate performance induced by its low intrinsic conductivity.Herein,we propose an ingenious strategy targeting superior SIBs through cross-linked NVPF with multi-dimensional nanocarbon frameworks composed of amorphous carbon and carbon nanotubes(NVPF@C@CNTs).This rational design ensures favorable particle size for shortened sodium ion transmission pathway as well as improved electronic transfer network,thus leading to enhanced charge transfer kinetics and superior cycling stability.Benefited from this unique structure,significantly improved electrochemical properties are obtained,including high specific capacity(126.9 mAh g-1 at 1 C,1 C=128 mA g-1)and remarkably improved long-term cycling stability with 93.9％capacity retention after 1000 cycles at 20 C.The energy density of 286.8 Wh kg-1 can be reached for full cells with hard carbon as anode(NVPF@C@CNTs//HC).Additionally,the electrochemical performance of the full cell at high temperature is also investigated(95.3 mAh g-1 after 100 cycles at 1 C at 50 ℃).Such nanoscale dual-carbon networks engineering and thorough discussion of ion diffusion kinetics might make contributions to accelerating the process of phosphate cathodes in SIBs for large-scale energy storages.
查看更多>>摘要：Si anode is of paramount importance for advanced energy-dense lithium-ion batteries(LIBs).However,the large volume change as well as stress generates during its lithiation-delithiation process poses a great challenge to the long-term cycling and hindering its application.Herein this work,a composite binder is prepared with a soft component,guar gum(GG),and a rigid linear polymer,anionic polyacrylamide(APAM).Rich hydroxy,carboxyl,and amide groups on the polymer chains not only enable intermolecular crosslinking to form a web-like binder,A2G1,but also realize strong chemical binding as well as physical encapsulating to Si particles.The resultant electrode shows limited thickness change of merely 9％on lithiation and almost recovers its original thickness on delithiation.It demonstrates high reversible capacity of 2104.3 mAh g-1 after 100 cycles at a current density of 1800 mA g-1,and in constant capacity(1000 mAh g-1)test,it also shows a long life of 392 cycles.Therefore,this soft-hard combining web-like binder illustrates its great potential in the future applications.
查看更多>>摘要：Slurry casting has been used to fabricate lithium-ion battery electrodes for decades,which involves toxic and expensive organic solvents followed by high-cost vacuum drying and electrode calendering.This work presents a new manufacturing method using a nonthermal plasma to create inter-particle binding without using any polymeric binding materials,enabling solvent-free manufacturing electrodes with any electrochemistry of choice.The cold-plasma-coating technique enables fabricating electrodes with thickness(＞200 pm),high mass loading(＞30 mg cm-2),high peel strength,and the ability to print lithium-ion batteries in an arbitrary geometry.This crosscutting,chemistry agnostic,platform technology would increase energy density,eliminate the use of solvents,vacuum drying,and calendering processes during production,and reduce manufacturing cost for current and future cell designs.Here,lithium iron phosphate and lithium cobalt oxide were used as examples to demonstrate the efficacy of the cold-plasma-coating technique.It is found that the mechanical peel strength of cold-plasma-coating-manufactured lithium iron phosphate is over an order of magnitude higher than that of slurry-casted lithium iron phosphate electrodes.Full cells assembled with a graphite anode and the cold-plasma-coating-lithium iron phosphate cathode offer highly reversible cycling performance with a capacity retention of 81.6％over 500 cycles.For the highly conductive cathode material lithium cobalt oxide,an areal capacity of 4.2 mAh cm-2 at 0.2 C is attained.We anticipate that this new,highly scalable manufacturing technique will redefine global lithium-ion battery manufacturing providing significantly reduced plant footprints and material costs.
查看更多>>摘要：Silver-zinc(Ag-Zn)batteries are a promising battery system for flexible electronics owing to their high safety,high energy density,and stable output voltage.However,poor cycling performance,low areal capacity,and inferior flexibility limit the practical application of Ag-Zn batteries.Herein,we develop a flexible quasi-solid-state Ag-Zn battery system with superior performance by using mild electrolyte and binder-free electrodes.Copper foam current collector is introduced to impede the growth of Zn dendrite,and the structure of Ag cathode is engineered by electrodeposition and chloridization process to improve the areal capacity.This novel battery demonstrates a remarkable cycle retention of 90％for 200 cycles at 3 mA cm-2.More importantly,this binder-free battery can afford a high capacity of 3.5 mAh cm-2 at 3 mA cm-2,an outstanding power density of 2.42 mW cm-2,and a maximum energy density of 3.4 mWh cm-2.An energy management circuit is adopted to boost the output voltage of a single battery,which can power electronic ink display and Bluetooth temperature and humidity sensor.The developed battery can even operate under the extreme conditions,such as being bent and sealed in solid ice.This work offers a path for designing electrodes and electrolyte toward high-performance flexible Ag-Zn batteries.
查看更多>>摘要：Rechargeable Zn-air batteries(ZAB)have drawn extensive attention due to their eco-friendliness and safety.However,the lack of high-performance and low-cost oxygen redox reactions(OER and ORR)catalysts has become one of the main stumbling blocks in their development.Herein,we successfully fabricate a CoFe nanobubble encapsulated in nitrogen-doped carbon nanocage on wood carbon support(CoFe@NC/WC)via pyrolysis of a novel Prussian blue analog(PBA)/spruce precursor.The hierarchical CoFe@NC/WC catalyst exhibits an excellent potential difference of 0.74 V between the OER potential at 10 mA cm-2 and half-wave potential of ORR in 0.1 M KOH,comparable to recently reported preeminent electrocatalysts.Further,CoFe@NC/WC shows outstanding electrochemical performance in liquid ZAB,with a peak power density of 138.9 mW cm-2 and a specific capacity of 763.5 mAh g-1.More importantly,a bacterial cellulose nanofiber reinforced polyacrylic acid(BC-PAA)hydrogel electrolyte shows ultrahigh tensile-breaking stress of 1.58 MPa.In conjunction with the as-prepared CoFe@NC/WC catalyst,BC-PAA-based wearable ZAB displays impressive rechargeability and foldability,and can power portable electronics,such as electronic timer and mobile phone,in bent states.This work provides a new approach toward high-activity and low-cost catalysts for ZAB.
查看更多>>摘要：Lithium metal batteries have been considered as one of the most promising next-generation power-support devices due to their high specific energy and output voltage.However,the uncontrollable side-reaction and lithium dendrite growth lead to the limited serving life and hinder the practical application of lithium metal batteries.Here,a tri-monomer copolymerized gel polymer electrolyte(TGPE)with a cross-linked reticulation structure was prepared by introducing a cross-linker(polyurethane group)into the acrylate-based in situ polymerization system.The soft segment of polyurethane in TGPE enables the far migration of lithium ions,and the-NH forms hydrogen bonds in the hard segment to build a stable cross-linked framework.This system hinders anion migration and leads to a high Li+migration number(tLi+=0.65),which achieves uniform lithium deposition and effectively inhibits lithium dendrite growth.As a result,the assembled symmetric cell shows robust reversibility over 5500 h at a current density of 1 mA cm-2.The LFP∷TGPE∷Li cell has a capacity retention of 89.8％after cycling 800 times at a rate of 1C.In summary,in situ polymerization of TGPE electrolytes is expected to be a candidate material for high-energy-density lithium metal batteries.
查看更多>>摘要：Organic redox compounds are attractive cathode materials in aqueous zinc-ion batteries owing to their low cost,environmental friendliness,multiple-electron-transfer reactions,and resource sustainability.However,the realized energy density is constrained by the limited capacity and low voltage.Herein,copper-tetracyanoquinodimethane(CuTCNQ),an organic charge-transfer complex is evaluated as a zinc-ion battery cathode owing to the good electron acceptation ability in the cyano groups that improves the voltage output.Through electrochemical activation,electrolyte optimization,and adoption of graphene-based separator,CuTCNQ-based aqueous zinc-ion batteries deliver much improved rate performance and cycling stability with anti-self-discharge properties.The structural evolution of CuTCNQ during discharge/charge are investigated by ex situ Fourier transform infra-red(FT-IR)spectra,ex situ X-ray photoelectron spectroscopy(XPS),and in situ ultraviolet visible spectroscopy(UV-vis),revealing reversible redox reactions in both cuprous cations(Cu+)and organic anions(TCNQx-1),thus delivering a high voltage output of 1.0 V and excellent discharge capacity of 158 mAh g-1.The remarkable electrochemical performance in Zn//CuTCNQ is ascribed to the strong inductive effect of cyano groups in CuTCNQ that elevated the voltage output and the graphene-modified separator that inhibited CuTCNQ dissolution and shuttle effect in aqueous electrolytes.
查看更多>>摘要：Sodium dentrite formed by uneven plating/stripping can reduce the utilization of active sodium with poor cyclic stability and,more importantly,cause internal short circuit and lead to thermal runaway and fire.Therefore,sodium dendrites and their related problems seriously hinder the practical application of sodium metal batteries(SMBs).Herein,a design concept for the incorporation of metal-organic framework(MOF)in polymer matrix(polyvinylidene fluoride-hexafluoropropylene)is practiced to prepare a novel gel polymer electrolyte(PH@MOF polymer-based electrolyte[GPE])and thus to achieve high-performance SMBs.The addition of the MOF particles can not only reduce the movement hindrance of polymer chains to promote the transfer of Na+but also anchor anions by virtue of their negative charge to reduce polarization during electrochemical reaction.A stable cycling performance with tiny overpotential for over 800 h at a current density of 5 mA cm-2 with areal capacity of 5 mA h cm-2 is achieved by symmetric cells based on the resulted GPE while the Na3V2O2(PO4)2F@rGO(NVOPF)|PH@MOF|Nacell also displays impressive specific cycling capacity(113.3 mA h g-1 at 1 C)and rate capability with considerable capacity retention.
查看更多>>摘要：The increasing demand for short charging time on electric vehicles has motivated realization of fast chargeable lithium-ion batteries(LIBs).However,shortening the charging time of LIBs is limited by Li+intercalation process consisting of liquid-phase diffusion,de-solvation,SEI crossing,and solid-phase diffusion.Herein,we propose a new strategy to accelerate the de-solvation step through a control of interaction between polymeric binder and solvent-Li+complexes.For this purpose,three alkali metal ions(Li+,Na+,and K+)substituted carboxymethyl cellulose(Li-,Na-,and K-CMC)are prepared to examine the effects of metal ions on their performances.The lowest activation energy of de-solvation and the highest chemical diffusion coefficient were observed for Li-CMC.Specifically,Li-CMC cell with a capacity of 3 mAh cm-2 could be charged to＞95％in 10 min,while a value above＞85％was observed after 150 cycles.Thus,the presented approach holds great promise for the realization of fast charging.
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