查看更多>>摘要：TiO2 nanoparticles doped with different con-centrations of Rb were prepared by sol-gel method.The crystal structures of samples were characterized by X-ray diffraction(XRD)and transmission electron microscopy(TEM).It was confirmed by the Rietveld refinement method that the as-prepared samples crystallize in anatase phase and Rb doping induces expansion and distortion of the crystal lattice.Compared with the pure TiO2,the Rb-doped nanoparticles have smaller crystal size and better dispersibility.Degradation rate of methylene blue was used to evaluate the photocatalytic activity of Rb-TiO2.It indicated that doping Rb into TiO2 can effectively improve the photocatalytic activity of TiO2 and the mechanisms were discussed in detail.When using the sample doped with 0.20％Rb,methylene blue degraded with the fastest rate(97％within 60 min).
查看更多>>摘要：Uncontrolled growth of lithium dendrite will lead to low Coulombic efficiency and poor cycle stability,which hinders the commercialization of lithium metal batteries.Herein,a novel modified lithium anode with reduced graphene oxide conductive network containing trace lithiophilic phosphorus(P-rGO/Cu)is prepared by electrospraying technique combined with heat treatment process.The rGO layer has a concave and undulating conductive structure,which can significantly improve the effective electrical contact between lithium metal and the current collector,speed up the kinetics of interfacial elec-tron transport and reaction,and improve the resistance of the negative electrode to the internal stress caused by volume change of the lithium,which is advantageous for the stability of the SEI film.The extremely small and uniformly distributed red phosphorus element avoids the volume change caused by lithiation to the maximum extent.Lithiophilic two-phase compound Li3P obtained by alloying P with Li can directionally induce the homoge-neous nucleation and dense deposition of lithium metal,address the issue of lithium dendrites and extend the cycle life of the batteries.The obtained P-rGO/Cu exhibits excellent electrochemical performance with an average Coulombic efficiency(CE)of 98％at a current density of 1 mA.cm-2 for 400 cycles,and the capacity retention rate of the full cell matched with lithium iron phosphate(LFP)is 83％after 400 cycles at 1C.
查看更多>>摘要：The high energy density and stability of solid-state lithium metal batteries(SSLMBs)have garnered great attention.Garnet-type oxides,especially Li6.4La3Zr1.4-Ta0.6O12(LLZTO),with high ionic conductivity,wide electrochemical window,and stability to Li metal anode,are promising solid-state electrolyte(SSEs)materials for SSLMBs.However,Li/LLZTO interface issues including high interface resistance,inhomogeneous Li deposition,and Li dendrite growth have hindered the practical appli-cation of SSLMBs.Herein,a multi-functional Li-SnF2 composite anode with Li,LiF,and Li-Sn alloy was specifically designed and prepared.The composite anode improves the wettability to LLZTO,constructing an intimate contact interface between it and LLZTO.Mean-while,ionic/electronic conductive paths in situ formed at the interface can effectively uniform Li deposition and suppress Li dendrite.The solid-state symmetric cell exhi-bits low interface resistance(11 Ω·cm2)and high critical current density(1.3 mA·cm-2)at 25 ℃.The full SSLMB based on LiFePO4 or LiNi0.5Co0.2Mn0.3O2 cathode also shows stable cycling performance and high rate capability.This work provides a new composite anode strategy for achieving high-energy density and high-safety SSLMBs.
查看更多>>摘要：In the current situation where the practical application of silicon anode materials encounters great challenges,silicon oxide(SiOx,0 ≤ x ≤ 2)has attracted the attention of researchers due to its relatively small volume expansion,stable cycling performance,and low cost,which is possible to realize commercial applications earlier than silicon anode.However,it remains a challenge to prepare SiOx materials with long-term stable cycling performance and high Coulombic efficiency using low-cost methods.In this work,SiOx anode material with high Coulombic efficiency and good long-term cycling stability was prepared at a low cost by hydrolysis of siloxane and in situ polymerization of phenolic resin.The hydrolysis of siloxane was further regulated by different silane coupling agents to regulate the size and microstructure of prepared SiOx materials,which displayed the substantially improved electrochemical performance.The excellent electrochemi-cal performance of SiOx prepared by regulated hydrolysis of siloxane with silane coupling agents is attributed to the effect of silane coupling agent on size and microstructure of SiOx,revealing that the strategy of modulating the hydrolysis of siloxane by silane coupling agent is a potential method to prepare high-performance SiOx materials.
查看更多>>摘要：Spinel MnCo2O4 is a promising energy storage candidate as anode materials in lithium-ion batteries owing to synergistic effects of two intrinsic solid-state redox couples.However,low conductivity,poor rate capacity and rapid capacity fading have seriously impaired its practical applications.To overcome the inferiorities,urchin-like MnCo2O4@C core-shell nanowire arrays have been fab-ricated directly within a porous copper current collector via a facile hydrothermal method followed by a chemical vapor deposition carbonization process.In a typical nano-wire,the core is composed of interconnected MnCo2O4 nanoparticles and the shell shows as a thin amorphous carbon layer.The integrated MnCo2O4@C/Cu structure could act as working anodes without using additives or polymer binders.While MnCo2O4@C/Cu possesses slightly longer Li-ion insertion/desertion pathway than that of MnCo2O4/Cu,the carbon shell could effectively prevent the pulverization of MnCo2O4 and lower down charge transfer resistance and actively participate in Li-ion cycles.The rearrangement of carbon atoms during lithiation/delithiation cycling could inhibit the formation of passive solid electrolyte interphase films.As a result,the MnCo2O4@C/Cu electrode presents superior rate capacity(600 mAh·g-1 at 1 A·g-1)and better stability(797 mAh·g-1 after 200 cycles at 100 mA·g-1).The excellent reversible Li ion storage capacity,cycling stability and rate capacity endow MnCo2O4@C/Cu great potential as stable and high output integrated anode materials in Li-ion batteries.
查看更多>>摘要：Transition metal sulfide(TMS)anodes exhibit the characteristics of phase stability and high capacity for lithium/sodium-ion batteries(LIBs/SIBs).However,the TMS anodes often suffer from poor electronic conductiv-ity,low ionic diffusion and large volume expansion during Li/Na-ion intercalation significantly impairing the Li/Na-storage performance.Herein,a long chain heterostructure composed of the Co9S8 and SnS are first reported,which can generate rich phase interfaces,and small crystal domains.The unique structure can facilitate the properties of reactivity,conductivity and ionic diffusion.In addition,the heterostructure surface is modified by the N-doped carbon(N-DC@(CoSn)S),successfully improving the structural stability.The synergistic effects of Co9S8/SnS heterostructure and coated carbon layer effectively increase the capacity and cycling stability.The N-DC@(CoSn)S anode delivers enhanced high specific capacities of 820.6 mAh·g-1 at 1.0 A·g-1 after 500 cycles for LIBs and 339.2 mAh·g-1 at 0.5 A·g-1 after 1000 cycles for SIBs,respectively.This work is expected to provide a material design idea for preparing LIBs/SIBs with high capacity and long cycling life.
查看更多>>摘要：High-energy-density Li-S batteries are sub-jected to serious sulfur deactivation and short cycle lifetime caused by undesirable polysulfide shuttle effect and frantic lithium dendrite formation.In this work,a controllable cage-confinement strategy to fabricate molybdenum car-bide(MoC)nanoclusters as a high-efficient sulfiphilic and lithiophilic regulator to mitigate the formidable issues of Li-S batteries is demonstrated.The sub-2 nm MoC nan-oclusters not only guarantee robust chemisorption and fast electrocatalytic conversion of polysulfides to enhance the sulfur electrochemistry,but also homogenize Li+flux to suppress the lithium dendrite growth.As a consequence,the MoC-modified separator endows the batteries with boosted reaction kinetics,promoted sulfur utilization,and improved cycling stability.A reversible capacity of 701 mAh·g-1 at a high rate of 5.0C and a small decay rate of 0.076％per cycle at 1.0C over 600 cycles are achieved.This study offers a rational route for design and synthesis of bifunctional nanoclusers with both sulfiphilicity and lithiophilicity for high-performance Li-S batteries.
查看更多>>摘要：Aqueous zinc-ion batteries(AZIBs)have attracted widespread attention due to the advantages of high safety and environmental friendliness.Although V2O3 is a promising cathode,the strong electrostatic interaction between Zn2+and V2O3 crystal,and the sluggish reaction kinetics still limit their application in AZIBs.Herein,the oxygen defects rich V2O3 with conducive poly(3,4-ethylenedioxythiophene)(PEDOT)shell(V2O3-Od@PE-DOT)was fabricated for AZIBs by combining the sulfur-assisted thermal reduction and in-situ polymerization method.The introduced oxygen vacancies of V2O3-Od@PEDOT weaken the electrostatic interaction between Zn2+and the host material,improving the interfacial electron transport,while the PEDOT coating enhances the structural stability and conductivity of V2O3,thus accel-erating the reaction kinetics.Based on the advantages,V2O3-Od@PEDOT electrode delivers a reversible capacity of 495 mAh·g-1 at 0.1 A·g-1,good rate capability(189 mAh·g-1 at 8.0 A·g-1),and an impressive cycling stability with 90.1％capacity retention over 1000 cycles at 8.0 A·g-1.The strategy may provide a path for exploiting the other materials for high performance AZIBs.
查看更多>>摘要：Owing to its high theoretical capacity and low cost,Sn has attracted significant attention in sodium-ion batteries.However,the slow kinetics of electrochemical reactions and the rapid decay of capacity resulting from drastic changes in the volume of Sn,as well as persistent side reactions between Sn and the organic electrolyte during the(de)sodium process,have limited its commer-cialization.To improve the electrochemical performance of Sn-based materials,the bottom-up method is normally used to prepare carbon-coated nanoparticles.However,its complex preparation processes and harsh conditions make it unsuitable for practical applications.Herein,a carbon-coated hybrid crystal composite(Sn/SnOx@C)was pre-pared using an up-bottom method with commercial Sn/SnO nanoparticles.Various effects accelerate the electrochem-ical kinetics and inhibit the coarsening of Sn crystals.The Sn/SnOx@C composite electrode exhibited capacity retention of 80.7％even after approximately 1000 cycles(360.4 mAh·g-1)at a current density of 1 A·g-1.The high-load Na3V2(PO4)3‖Sn/SnOx@C full cell presents a capacity retention rate of 91.7％after 150 cycles at the current density of 0.5 A·g-1.This work may significantly accel-erate the commercialization of the Sn/SnOx@C composite in sodium-ion batteries with high energy density.
查看更多>>摘要：Ultra-high nickel layered oxide cathode mate-rial with high energy density is the most promising material to improve the electrochemical performance of lithium-ion batteries(LIBs).However,the poor structural stability and severe surface/interface side reactions of the material lead to poor rate performance and cyclic stability,which limits its application in practice.In this paper,the dual-modifi-cation strategy of Co doping and La2O3 coating is used to meet the above challenges.Co doping can effectively widen layer spacing and reduce Li+/Ni2+mixing,and La2O3 coating can effectively eliminate the residual alkali on the surface of active material,inhibit the thickening of cathode electrolyte interphase(CEI)film and reduce sur-face/interface side reactions.Therefore,the modified material(NM90-CL)with excellent electrochemical prop-erties is achieved through the synergistic enhancement of Co doping and La2O3 coating.Its capacity retention rate can reach 77.9％after 200 cycles at 1.0 ℃ and 75.7％after 200 cycles at 5.0 ℃.Its reversible capacity can up to 153.5 mAh·g-1 at 10.0 ℃.This dual-modification strategy will provide theoretical guidance and technical support for the synthesis of other high-performance electrode materials.
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