Understanding the proton dynamic behavior in inorganic materials has long been a topic of intense fascination[1],especially in the field of electrochemical energy storage[2].One of the examples is the research of prot...Understanding the proton dynamic behavior in inorganic materials has long been a topic of intense fascination[1],especially in the field of electrochemical energy storage[2].One of the examples is the research of proton transport in transition metal oxides,which dates back to 1971[3]when RuO_(2) was discovered to be capable of storing protons via reversible redox reactions[4].In aqueous electrolytes,the thin film RuO_(2) electrode exhibits a surface pseudocapacitive behavior[5],which could be modified by the structural water in its hydrated form due to the facile Grotthuss hopping mode of protons along the established hydrogen bonds inside the bulk phase[6].Soon later,Goodenough et al.reported the capacitor-like behavior of amorphous MnO_(2)·xH_(2)O electrode in an aqueous KCl electrolyte[7],and further studies on the hydrated MnO_(2) electrodes prepared by sol-gel processes have soon discovered that the intercalation of protons from aqueous electrolytes plays an indispensable role in the charge storage mechanism[8].In recent years,the research interest on rechargeable aqueous batteries has fueled the renaissance of mechanistic study of proton transport in transition metal oxides[9],which can operate as cathodes or anodes via a topotactic insertion mechanism similar to that in Li-ion batteries[10].However,due to the challenges for experimental detection of local chemical environments of the inserted protons,a comprehensive understanding of proton dynamic behavior in these electrodes remains largely lacking.展开更多
Prussian blue and Prussian blue analogs are widely used in sodium-ion batteries(SIBs).In this study,we upcycle the degraded Prussian blue directly into layered materials for SIBs through thermal treatment.Prussian blu...Prussian blue and Prussian blue analogs are widely used in sodium-ion batteries(SIBs).In this study,we upcycle the degraded Prussian blue directly into layered materials for SIBs through thermal treatment.Prussian blue thermally decomposes to form metal oxides,which then recrystallize into layered metal oxides with metal-nitrogen bond on their surface under suitable temperature conditions.This transformation method is similar to solid-state synthesis,allowing for the pre-addition of necessary components before material conversion to optimize the composition and integrity of the target materials.Based on in situ x-ray diffraction observations of the crystal structure changes of Prussian blue at different temperatures,we demonstrate 1,000℃as the optimal temperature for converting to layered materials.These materials exhibit an initial discharge capacity of 122.3 mAh g^(-1)and good rate and cycling stability.We hope that this research will promote the sustainable development of the SIB industry.展开更多
Magnetic resonance(MR)imaging,with its inherent good spatial resolution and without tissue penetration depth limitations associated with other cell tracking techniques,is considered a valuable tool to assess the effec...Magnetic resonance(MR)imaging,with its inherent good spatial resolution and without tissue penetration depth limitations associated with other cell tracking techniques,is considered a valuable tool to assess the effects of cellular therapy.However,in order to allow in vivo tracking of transplanted cells with MRI,the cells must be labeled with contrast agents,usually in the form of magnetic or paramagnetic nanoparticles.Typically these are iron oxides,which are associated with a number of drawbacks related e.g.to the generation of hypointensities of the MR image due to signal loss.In this study,two chemically distinct manganese oxide-based nanostructures were developed and their feasibility as labels for human mesenchymal stem cells(hMSCs)was investigated.The ability to monitor the produced particles alone or within the labeled cells in vitro using MR imaging was further evaluated.Two novel synthetic approaches,the polyol process and microwave digestion,were combined to yield a“green”,and extremely rapid means of producing water-dispersible crystalline(MnO)and amorphous(MnOx)manganese oxides.To increase their water dispersability,capping agents in the form of organic polymers,poly(vinyl pyrrolidone)(PVP)and poly(acrylic acid)(PAA),were added to the synthesis process.Crystalline MnO was not formed when PAA was used as the capping agent,since Mn ions(Mn^(2+))cannot be hydrolyzed to Mn(OH)_(2),which is an intermediate step in the formation of MnO,under the acidic conditions provided by PAA.PVP,on the other hand,served to induce a spherical shape to the formed nanocrystals.Remarkably,the relaxation times of the as-prepared amorphous MnOx were significantly shorter than those of their crystalline counterparts,and the biocompatibility was also higher for MnOx.To the best of our knowledge,this is the first report which describes the use of an amorphous MnOx as a cell label for MR imaging.展开更多
基金financial support from the National Natural Science Foundation of China(22109003)the Basic and Applied Basic Research Foundation of Guangdong Province(2023A1515011391)+1 种基金Soft Science Research Project of Guangdong Province(No.2017B030301013)the Major Science and Technology Infrastructure Project of Material Genome Big-science Facilities Platform supported by Municipal Development and Reform Commission of Shenzhen.
文摘Understanding the proton dynamic behavior in inorganic materials has long been a topic of intense fascination[1],especially in the field of electrochemical energy storage[2].One of the examples is the research of proton transport in transition metal oxides,which dates back to 1971[3]when RuO_(2) was discovered to be capable of storing protons via reversible redox reactions[4].In aqueous electrolytes,the thin film RuO_(2) electrode exhibits a surface pseudocapacitive behavior[5],which could be modified by the structural water in its hydrated form due to the facile Grotthuss hopping mode of protons along the established hydrogen bonds inside the bulk phase[6].Soon later,Goodenough et al.reported the capacitor-like behavior of amorphous MnO_(2)·xH_(2)O electrode in an aqueous KCl electrolyte[7],and further studies on the hydrated MnO_(2) electrodes prepared by sol-gel processes have soon discovered that the intercalation of protons from aqueous electrolytes plays an indispensable role in the charge storage mechanism[8].In recent years,the research interest on rechargeable aqueous batteries has fueled the renaissance of mechanistic study of proton transport in transition metal oxides[9],which can operate as cathodes or anodes via a topotactic insertion mechanism similar to that in Li-ion batteries[10].However,due to the challenges for experimental detection of local chemical environments of the inserted protons,a comprehensive understanding of proton dynamic behavior in these electrodes remains largely lacking.
基金supported by the Shenzhen Science and Technology Program(KCXST20221021111201003 and KJZD20230923114107014)National Natural Science Foundation of China(nos.52261160384,52072208,and 22379085)+3 种基金Fundamental Research Project of Shenzhen(no.JCYJ20220818101004009)Guangdong Basic and Applied Basic Research Foundation(no.2022A1515110531)China Postdoctoral Science Foundation(no.2022M721800)support of the Major Science and Technology Infrastructure Project of Material Genome Big-science Facilities Platform supported by Municipal Development and Reform Commission of Shenzhen.
文摘Prussian blue and Prussian blue analogs are widely used in sodium-ion batteries(SIBs).In this study,we upcycle the degraded Prussian blue directly into layered materials for SIBs through thermal treatment.Prussian blue thermally decomposes to form metal oxides,which then recrystallize into layered metal oxides with metal-nitrogen bond on their surface under suitable temperature conditions.This transformation method is similar to solid-state synthesis,allowing for the pre-addition of necessary components before material conversion to optimize the composition and integrity of the target materials.Based on in situ x-ray diffraction observations of the crystal structure changes of Prussian blue at different temperatures,we demonstrate 1,000℃as the optimal temperature for converting to layered materials.These materials exhibit an initial discharge capacity of 122.3 mAh g^(-1)and good rate and cycling stability.We hope that this research will promote the sustainable development of the SIB industry.
基金Svenska Tekniska Vetenskapsakademien i Finland r.f.,Tekniikan Edistämissäätiö,and the Academy of Finland(project#260599)are acknowledged for financial support(J.M.R.).
文摘Magnetic resonance(MR)imaging,with its inherent good spatial resolution and without tissue penetration depth limitations associated with other cell tracking techniques,is considered a valuable tool to assess the effects of cellular therapy.However,in order to allow in vivo tracking of transplanted cells with MRI,the cells must be labeled with contrast agents,usually in the form of magnetic or paramagnetic nanoparticles.Typically these are iron oxides,which are associated with a number of drawbacks related e.g.to the generation of hypointensities of the MR image due to signal loss.In this study,two chemically distinct manganese oxide-based nanostructures were developed and their feasibility as labels for human mesenchymal stem cells(hMSCs)was investigated.The ability to monitor the produced particles alone or within the labeled cells in vitro using MR imaging was further evaluated.Two novel synthetic approaches,the polyol process and microwave digestion,were combined to yield a“green”,and extremely rapid means of producing water-dispersible crystalline(MnO)and amorphous(MnOx)manganese oxides.To increase their water dispersability,capping agents in the form of organic polymers,poly(vinyl pyrrolidone)(PVP)and poly(acrylic acid)(PAA),were added to the synthesis process.Crystalline MnO was not formed when PAA was used as the capping agent,since Mn ions(Mn^(2+))cannot be hydrolyzed to Mn(OH)_(2),which is an intermediate step in the formation of MnO,under the acidic conditions provided by PAA.PVP,on the other hand,served to induce a spherical shape to the formed nanocrystals.Remarkably,the relaxation times of the as-prepared amorphous MnOx were significantly shorter than those of their crystalline counterparts,and the biocompatibility was also higher for MnOx.To the best of our knowledge,this is the first report which describes the use of an amorphous MnOx as a cell label for MR imaging.
