Prussian blue analogs(PBAs)are potential contestants for aqueous Mg-ion batteries(AMIBs)on account of their high discharge voltage and threedimensional open frameworks.However,the low capacity arising from single reac...Prussian blue analogs(PBAs)are potential contestants for aqueous Mg-ion batteries(AMIBs)on account of their high discharge voltage and threedimensional open frameworks.However,the low capacity arising from single reaction site severely restricts PBAs'practical applications in highenergy-density AMIBs.Here,an organic acid co-coordination combined with etching method is reported to fabricate defect-rich potassium-free copper hexacyanoferrate with structural water on carbon nanotube fiber(DCuHCF@CNTF).Benefiting from the high-valence-state reactive sites,arrayed structure and defect effect,the well-designed D-CuHCF@CNTF exhibits an extraordinary reversible capacity of 146.6 mAh g1 with two-electron reaction,nearly close to its theoretical capacity.It is interesting to unlock the reaction mechanism of the Fe2+/Fe3+and Cu+/Cu2+redox couples via x-ray photoelectron spectroscopy.Furthermore,density functional theory calculations reveal that Fe and Cu in potassium-free D-CuHCF participate in charge transfer during the Mg2+insertion/extraction process.As a proof-of-concept demonstration,a rocking-chair fiber-shaped AMIBs was constructed via coupling with the NaTi2(PO4)3/CNTF anode,achieving high energy density and impressive mechanical flexibility.This work provides new possibilities to develop potassium-free PBAs with dual-active sites as high-capacity cathodes for wearable AMIBs.展开更多
Two-electron neutral aqueous organic redox flow batteries(AORFBs)hold more promising applications in the power grid than one-electron batteries because of their higher capacity.However,their development is strongly li...Two-electron neutral aqueous organic redox flow batteries(AORFBs)hold more promising applications in the power grid than one-electron batteries because of their higher capacity.However,their development is strongly limited by the structural instability of the highly reduced species.By combining the extendedπ-conjugation structure of the anolytes and the enhanced aromaticity of the highly reduced species,we reported a series of highly conjugated and inexpensive arylene diimide derivatives(NDI,PDI,and TPDI)as novel two-electron storage anolyte materials for ultrastable AORFBs.Matched with(ferrocenylmethyl)trimethylammonium chloride(FcNCl)as catholyte,arylene diimide derivative-based AORFBs showed the highest stability in two-electron AORFBs to date.The NDI/FcNCl-based AORFB delivered 98.44%capacity retention at 40 mA cm^(−2)for 350 cycles;TPDI/FcNCl-based AORFB also showed remarkable stability with 97.22%capacity retention at 20 mA cm^(−2)over 200 cycles.This finding lays the theoretical foundation and offers a reference for improving the stability of two-electron AORFBs.展开更多
基金National Key R&D Program of China,Grant/Award Number:2022YFA1203304Natural Science Foundation of Jiangsu Province,Grant/Award Number:BK20220288Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences,Grant/Award Number:E1552102。
文摘Prussian blue analogs(PBAs)are potential contestants for aqueous Mg-ion batteries(AMIBs)on account of their high discharge voltage and threedimensional open frameworks.However,the low capacity arising from single reaction site severely restricts PBAs'practical applications in highenergy-density AMIBs.Here,an organic acid co-coordination combined with etching method is reported to fabricate defect-rich potassium-free copper hexacyanoferrate with structural water on carbon nanotube fiber(DCuHCF@CNTF).Benefiting from the high-valence-state reactive sites,arrayed structure and defect effect,the well-designed D-CuHCF@CNTF exhibits an extraordinary reversible capacity of 146.6 mAh g1 with two-electron reaction,nearly close to its theoretical capacity.It is interesting to unlock the reaction mechanism of the Fe2+/Fe3+and Cu+/Cu2+redox couples via x-ray photoelectron spectroscopy.Furthermore,density functional theory calculations reveal that Fe and Cu in potassium-free D-CuHCF participate in charge transfer during the Mg2+insertion/extraction process.As a proof-of-concept demonstration,a rocking-chair fiber-shaped AMIBs was constructed via coupling with the NaTi2(PO4)3/CNTF anode,achieving high energy density and impressive mechanical flexibility.This work provides new possibilities to develop potassium-free PBAs with dual-active sites as high-capacity cathodes for wearable AMIBs.
基金supported by the Natural Science Foundation of China(grant nos.22175138 and 21875180)the National Key Research and Development Program of China(grant no.2021YFB3200700)+4 种基金the Key Research and Development Program of Shaanxi(grant no.2021GXLH-Z023)the Independent Innovation Capability Improvement Project of Xi’an Jiaotong University(grant no.PY3A066)the Fundamental Research Funds for the Central Universities(grant no.xhj032021008-03)the Regional Innovation Capability Guidance Program of Shaanxi Province the Fundamental(grant no.2022QFY08-01)the Research Funds for the Central Universities(grant no.xzy022022001).
文摘Two-electron neutral aqueous organic redox flow batteries(AORFBs)hold more promising applications in the power grid than one-electron batteries because of their higher capacity.However,their development is strongly limited by the structural instability of the highly reduced species.By combining the extendedπ-conjugation structure of the anolytes and the enhanced aromaticity of the highly reduced species,we reported a series of highly conjugated and inexpensive arylene diimide derivatives(NDI,PDI,and TPDI)as novel two-electron storage anolyte materials for ultrastable AORFBs.Matched with(ferrocenylmethyl)trimethylammonium chloride(FcNCl)as catholyte,arylene diimide derivative-based AORFBs showed the highest stability in two-electron AORFBs to date.The NDI/FcNCl-based AORFB delivered 98.44%capacity retention at 40 mA cm^(−2)for 350 cycles;TPDI/FcNCl-based AORFB also showed remarkable stability with 97.22%capacity retention at 20 mA cm^(−2)over 200 cycles.This finding lays the theoretical foundation and offers a reference for improving the stability of two-electron AORFBs.
