Lithium‑sulfur batteries(LSBs)offer high theoretical energy density but suffer rapid capacity fading caused by sluggish sulfur redox kinetics,polysulfide shuttling,and electrode passivation.Here,a thermally activated ...Lithium‑sulfur batteries(LSBs)offer high theoretical energy density but suffer rapid capacity fading caused by sluggish sulfur redox kinetics,polysulfide shuttling,and electrode passivation.Here,a thermally activated V2O5/multiwalled carbon nanotube(MWCNT)hybrid composite is engineered as a polar‑conductive host to regulate oxide‑carbon interfacial coordination and sulfur redox behavior via a dual‑encapsulation strategy.Structural analysis using X‑ray diffraction with Rietveld refinement reveals enhanced crystallographic coherence and reduced microstrain,accompanied by modulation of the V‑O coordination environment.Raman and Fourier transform infrared spectroscopy indicate controlled evolution of carbon defects and V‑O bonding,while X‑ray photoelectron spectroscopy demonstrates an increased V4+/V5+ratio after thermal activation,indicating modification of surface electronic structure.The hybrid cathode delivers an initial capacity of 1665 mAh g-1at C/20 as well as 1596 mAh g-1at C/10,retaining~770 mAh g-1after 300 cycles at C/10.Symmetric‑cell measurements and Li2S nucleation analysis further support enhanced polysulfide conversion kinetics.Postmortem analysis confirms suppressed polysulfide deposition and preservation of conductive pathways after prolonged cycling.This study establishes a structure‑defect‑interfacial kinetics correlation,demonstrating that controlled thermal modulation of a binary oxide‑carbon framework provides an effective strategy for improving Li‑S battery performance.展开更多
Zn-based thermal charging devices,utilizing the synergistic effect of ion thermoextraction and thermodiffusion,are able to efficiently convert thermal energy into electrical energy and storage in the devices,making th...Zn-based thermal charging devices,utilizing the synergistic effect of ion thermoextraction and thermodiffusion,are able to efficiently convert thermal energy into electrical energy and storage in the devices,making them a highly promising technology for low-grade heat recovery and utilization.However,the low output power density and energy conversion efficiency resulted by the slow diffusion kinetics of Zn2+hinder their development.Herein,we present a highperformance thermal charging cell design using Zn2+/NH4+hybrid ion electrolyte,which not only maintains the high output voltage of the Zn-based thermoelectric system,but also significantly enhances the output power density due to the fast diffusion kinetics of NH4+.Based on this strategy,the thermal charging cell displays a high thermopower of 12.5 mV K-1and an excellent normalized power density of 19.6 mW m-2K-2at a temperature difference of 35 K.The Carnot-relative efficiency is as high as 12.74%.Moreover,it can operate continuously for over 72 h when the temperature difference persists,achieving a balance between thermoelectric conversion and output.This work provides a simple and effective strategy for the design of high-performance thermal charging cells for low-grade heat conversion and utilization.展开更多
Layered V2O5 cathode holds the merits of high theoretical specific capacity(589 mA h g-1)in aqueous zinc-ion batteries(AZIBs),yet it still suffers from inferior bulk conductivity and structure degradation not...Layered V2O5 cathode holds the merits of high theoretical specific capacity(589 mA h g-1)in aqueous zinc-ion batteries(AZIBs),yet it still suffers from inferior bulk conductivity and structure degradation notably during prolonged cycling.Herein,we ingeniously design cations(Na+/Co2+/Al3+)and anion(F-)synergistic-doped hydrated V2O5·0.48H2O cathode(VNACOF)to enhance the electronic and spatial effects in the bulk.A range of in-situ,ex-situ characterizations,and DFT calculations profoundly clarify the strengthened ionic/electronic conductivities,structural stability,and Zn2+diffusion kinetics.As a result,the VNACOF displays a superior discharge capacity(529 mA h g-1@0.1 C),rate capabilities(488 mA h g-1@0.5 C,437 mA h g-1@1C),and cycling stability(301 mA h g-1@10 C@5000 cycles@93%)with sufficient energy density(393 W h kg-1),Furthermore,the pouch-cells with high-load(60 mg)also deliver superior cyclic(2 C@178 mA h g-1@1000 cycles@90%)and rate performance(132 mA h g-1@5 C),revealing great application potential for high-energy-density and high-stability AZIBs.展开更多
利用水热合成法合成了分子组成为(C6H11NH3)5H(P2Mo5O23)4H2O的杂多化合物, 用单晶X-ray衍射方法测定了它的结构,该晶体属于单斜晶系,空间群P21/c, a = 12.830(3), b = 14.848(3), c = 25.258(5) ? b = 92.95(3), Mr = 1483.62, V = 480...利用水热合成法合成了分子组成为(C6H11NH3)5H(P2Mo5O23)4H2O的杂多化合物, 用单晶X-ray衍射方法测定了它的结构,该晶体属于单斜晶系,空间群P21/c, a = 12.830(3), b = 14.848(3), c = 25.258(5) ? b = 92.95(3), Mr = 1483.62, V = 4805.1(17) 3, Z = 4, Dc = 2.051 g/cm3, m = 1.431 mm-1, F(000) = 3000, I >2s(I) 的可观察衍射点4426个, 最终结构偏差因子R = 0.0464, wR = 0.0801, S = 0.731。在[P2Mo5O23]6-杂多阴离子中5个MoO6八面体通过共边和共角相连, 形成1个近似的五角平面骨架, 2个PO4四面体加在五角平面的两侧。热性质研究表明杂多阴离子骨架在547.4 ℃左右分解。展开更多
基金financial support from the U.S.National Aeronautics and Space Administration through the Established Program to Stimulate Competitive Research(NASA-EPSCoR),Puerto Rico,under Grant No.80NSSC24M0107the Department of Science and Technology Govt.of Rajasthan,Bharat for R&D Scheme(F24(1)/DST/R&D/2024/EAC/00378/6549873/712)。
摘要Lithium‑sulfur batteries(LSBs)offer high theoretical energy density but suffer rapid capacity fading caused by sluggish sulfur redox kinetics,polysulfide shuttling,and electrode passivation.Here,a thermally activated V2O5/multiwalled carbon nanotube(MWCNT)hybrid composite is engineered as a polar‑conductive host to regulate oxide‑carbon interfacial coordination and sulfur redox behavior via a dual‑encapsulation strategy.Structural analysis using X‑ray diffraction with Rietveld refinement reveals enhanced crystallographic coherence and reduced microstrain,accompanied by modulation of the V‑O coordination environment.Raman and Fourier transform infrared spectroscopy indicate controlled evolution of carbon defects and V‑O bonding,while X‑ray photoelectron spectroscopy demonstrates an increased V4+/V5+ratio after thermal activation,indicating modification of surface electronic structure.The hybrid cathode delivers an initial capacity of 1665 mAh g-1at C/20 as well as 1596 mAh g-1at C/10,retaining~770 mAh g-1after 300 cycles at C/10.Symmetric‑cell measurements and Li2S nucleation analysis further support enhanced polysulfide conversion kinetics.Postmortem analysis confirms suppressed polysulfide deposition and preservation of conductive pathways after prolonged cycling.This study establishes a structure‑defect‑interfacial kinetics correlation,demonstrating that controlled thermal modulation of a binary oxide‑carbon framework provides an effective strategy for improving Li‑S battery performance.
基金supported by the Leading Edge Technology of Jiangsu Province(BK20222009-X.Z.,BK20202008-X.Z.)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)National Undergraduate Innovation Training Program of NUAA(202410287179Y).
摘要Zn-based thermal charging devices,utilizing the synergistic effect of ion thermoextraction and thermodiffusion,are able to efficiently convert thermal energy into electrical energy and storage in the devices,making them a highly promising technology for low-grade heat recovery and utilization.However,the low output power density and energy conversion efficiency resulted by the slow diffusion kinetics of Zn2+hinder their development.Herein,we present a highperformance thermal charging cell design using Zn2+/NH4+hybrid ion electrolyte,which not only maintains the high output voltage of the Zn-based thermoelectric system,but also significantly enhances the output power density due to the fast diffusion kinetics of NH4+.Based on this strategy,the thermal charging cell displays a high thermopower of 12.5 mV K-1and an excellent normalized power density of 19.6 mW m-2K-2at a temperature difference of 35 K.The Carnot-relative efficiency is as high as 12.74%.Moreover,it can operate continuously for over 72 h when the temperature difference persists,achieving a balance between thermoelectric conversion and output.This work provides a simple and effective strategy for the design of high-performance thermal charging cells for low-grade heat conversion and utilization.
基金financially supported by the National Key Research and Development Program of China(2022YFA1505700,2019YFA0210403)the National Natural Science Foundation of China(52102216)+4 种基金the Natural Science Foundation of Fujian Province(2022J01625,2022-S-002)the Anhui Key Laboratory of Nanomaterials and Nanotechnology,the Major Science and Technology Projects in Anhui Province(202305a12020006)the Open Project of State Key Laboratory of Inorganic Synthesis and Preparative Chemistry(2025-22)the Innovation Training Program for College Students(cxxl-2024131,cxxl-2024136)support by Transmission Electron Microscope Platform and High-performance Computing Platform of Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China。
摘要Layered V2O5 cathode holds the merits of high theoretical specific capacity(589 mA h g-1)in aqueous zinc-ion batteries(AZIBs),yet it still suffers from inferior bulk conductivity and structure degradation notably during prolonged cycling.Herein,we ingeniously design cations(Na+/Co2+/Al3+)and anion(F-)synergistic-doped hydrated V2O5·0.48H2O cathode(VNACOF)to enhance the electronic and spatial effects in the bulk.A range of in-situ,ex-situ characterizations,and DFT calculations profoundly clarify the strengthened ionic/electronic conductivities,structural stability,and Zn2+diffusion kinetics.As a result,the VNACOF displays a superior discharge capacity(529 mA h g-1@0.1 C),rate capabilities(488 mA h g-1@0.5 C,437 mA h g-1@1C),and cycling stability(301 mA h g-1@10 C@5000 cycles@93%)with sufficient energy density(393 W h kg-1),Furthermore,the pouch-cells with high-load(60 mg)also deliver superior cyclic(2 C@178 mA h g-1@1000 cycles@90%)and rate performance(132 mA h g-1@5 C),revealing great application potential for high-energy-density and high-stability AZIBs.