With apical leaves of Lycium ruthenicum Murr as experimental material, the polyploids of L. ruthenicum were induced with colchicine solution, and total four polyploidy plants were identified by chromosome courts. The ...With apical leaves of Lycium ruthenicum Murr as experimental material, the polyploids of L. ruthenicum were induced with colchicine solution, and total four polyploidy plants were identified by chromosome courts. The results showed that tetraploid plants of L. ruthenicum were successfully induced with 300 mg/L of colchicine solution after 7 and 21 d of induction, with 400 mg/L of colchicine solution after 14 days of induction, and with 500 mg/L of colchicine solution after 7 days of induction, respectively.展开更多
Rechargeable aqueous batteries with high power density and energy density are highly desired for electrochemical energy storage.Despite the recent reports of various cathode materials with ultrahigh pseudocapacitance ...Rechargeable aqueous batteries with high power density and energy density are highly desired for electrochemical energy storage.Despite the recent reports of various cathode materials with ultrahigh pseudocapacitance exceeding3000 F g^(-1)(or 800 mA h g^(-1)),the development of anode materials is relatively insufficient,which limits the whole performance of the devices far from practical applications.Herein,we report the preparation of mesoporous Fe_(3)O_(4)@C nanoarrays as high-performance anode for rechargeable Ni/Fe battery by a self-generated sacrificial template method.Zn O/Fe_(3)O_(4)composite was first synthesized by a co-deposition process,and Zn O was subsequently removed by alkali etching to construct the mesoporous structure.A thin carbon film was introduced onto the surface of the electrode by the carbonization of glucose to increase the structural stability of the electrode.The unique mesoporous nanoarray architecture endows the electrode with larger specific surface area,faster charge/mass transport and higher utilization of Fe_(3)O_(4),which shows an ultrahigh specific capacity (292.4 mA h g^(-1)at a current density of 5 mA cm^(-2)) and superior stability in aqueous electrolyte (capacitance retention of 90.8%after 5000cycles).After assembled with hierarchical mesoporous Ni O nanoarray as a cathode,an optimized rechargeable Ni/Fe battery with double mesoporous nanoarray electrodes was fabricated,which provided high energy/power densities(213.3 W h kg^(-1)at 0.658 kW kg^(-1)and 20.7 kW kg^(-1)at113.9 W h kg^(-1),based on the total mass of the active materials)in the potential window of 1.5 V with excellent cyclability(81.7%retention after 5000 charge/discharge cycles).展开更多
Niobium pentoxide;Ion and electron transport;Mass loading;Areal capacity;Lithium-ion batteryNiobium pentoxide(Nb2 O5) has attracted great attention as an anode for lithium-ion battery, which is attributed to the high-...Niobium pentoxide;Ion and electron transport;Mass loading;Areal capacity;Lithium-ion batteryNiobium pentoxide(Nb2 O5) has attracted great attention as an anode for lithium-ion battery, which is attributed to the high-rate and good stability performances. In this work, TT-, T-, M-, and H-Nb2 O5 microspheres were synthesized by a facile one-step thermal oxidation method. Ion and electron transport properties of Nb2 O5 with different phases were investigated by both electrochemical analyses and density functional theoretical calculations. Without nanostructuring and carbon modification, the tetragonal Nb2 O5(M-Nb2 O5) displays preferable rate capability(121 m Ah g^-1 at 5 A g^-1), enhanced reversible capacity(163 m Ah g^-1 at 0.2 A g^-1) and better cycling stability(82.3% capacity retention after 1000 cycles)when compared with TT-, T-, and H-Nb2 O5. Electrochemical analyses further reveal the diffusioncontrolled Li+intercalation kinetics and in-situ X-ray diffraction analysis indicates superior structural stability upon Li+intercalation/deintercalation. Benefiting from the intrinsic fast ion/electron transport, a high areal capacity of 2.24 m Ah cm^-2 is obtained even at an ultrahigh mass loading of 22.51 mg cm^-2.This work can promote the development of Nb2 O5 materials for high areal capacity and stable lithium storage towards practical applications.展开更多
Potassium-ion batteries(PIBs) hold great potential as an alternative to lithium-ion batteries due to the abundant reserves of potassium and similar redox potentials of K+/K and Li+/Li. Unfortunately, PIBs with carbona...Potassium-ion batteries(PIBs) hold great potential as an alternative to lithium-ion batteries due to the abundant reserves of potassium and similar redox potentials of K+/K and Li+/Li. Unfortunately, PIBs with carbonaceous electrodes present sluggish kinetics, resulting in unsatisfactory cycling stability and poor rate capability. Herein, we demonstrate that the synergistic effects of the enlarged interlayer spacing and enhanced capacitive behavior induced by the co-doping of nitrogen and sulfur atoms into a carbon structure(NSC) can improve its potassium storage capability. Based on the capacitive contribution calculations, electrochemical impedance spectroscopy, the galvanostatic intermittent titration technique, and density functional theory results, the NSC electrode is found to exhibit favorable electronic conductivity,enhanced capacitive adsorption behavior, and fast K+ ion diffusion kinetics. Additionally, a series of exsitu characterizations demonstrate that NSC exhibits superior structural stability during the(de)potassiation process. As a result, NSC displays a high reversible capacity of 302.8 mAh g-1 at 0.1 Ag-1 and a stable capacity of 105.2 m Ahg-1 even at 2 Ag-1 after 600 cycles. This work may offer new insight into the effects of the heteroatom doping of carbon materials on their potassium storage properties and facilitate their application in PIBs.展开更多
Hierarchical flower-structured two-dimensional(2 D)nanosheet is favorable for electrochemical reactions.The unique structure not only exposes the maximized active sites and shortens ion/electron diffusion channels,but...Hierarchical flower-structured two-dimensional(2 D)nanosheet is favorable for electrochemical reactions.The unique structure not only exposes the maximized active sites and shortens ion/electron diffusion channels,but also inhibits the structural strain during cycling processes.Herein,we report the hierarchical flower-like pure spinel manganese-based oxide nanosheets synthesized via a template-orientated strategy.The oriented template is fabricated by decomposition of carbonate obtained from"bubble reaction",via an alcoholassisted hydrothermal process.The resultant spinel manganese-based oxide nanosheets simultaneously possess excellent rate capability and cycling stability.The high-voltage LiNi0.5Mn1.5O4(LNMO-HF)has a uniform phase distribution without the common impurity phase LixNi1-xO2 and NixO.Besides,the LNMO-HF delivers high discharge capacity of142.6 mA h g-with specific energy density of 660.7 W h kg 1 at 1 C under 55℃.More importantly,the template-orientated strategy can be extended to the synthesis of LiMn2 O4(LMO),which can achieve 88.12%capacity retention after 1000 cycles.展开更多
Li-ion hybrid supercapacitors （Li-HECs） facilitate effective combination of the advantages of supercapacitors and Li-ion batteries （LIBs）. However, challenges remain in designing and preparing suitable anode and c...Li-ion hybrid supercapacitors （Li-HECs） facilitate effective combination of the advantages of supercapacitors and Li-ion batteries （LIBs）. However, challenges remain in designing and preparing suitable anode and cathode materials, which often require tedious and expensive procedures. Herein, we demonstrated that hollow N-doped carbon capsules （HNC） with and without a Fe304 nanoparticle core can respectively function as the anode and the cathode in very-high-performance Li-HECs. The Fe3Oa@NC anode exhibited a high reversible specific capacity exceeding 1530 mA h g^-1 at 100 mA g^-1 and excellent rate capability （45% capacity retention from 0.1 to 5 A g^-1） and cycle stability （〉97% retention after 100 cycles）. Moreover, high rate performance was achieved in a full-cell using the HNC cathode. By combining the respective structural advantages of the components, the hybrid device with Fe3Oa@NC//HN C exhibited a remark- able energy density of 185 W h kg^-1 at a power density of 39 W kg^-1. The hybrid device furnished a battery-inaccessible power density of 28 kW kg^-1 with rapid charging/discharging within 9 s at an energy density of 95 W h kg^-1.展开更多
基金Supported by 2016 College Students’Innovative Entrepreneurial Training Program of Yanbian University(ydbksky2016127)~~
文摘With apical leaves of Lycium ruthenicum Murr as experimental material, the polyploids of L. ruthenicum were induced with colchicine solution, and total four polyploidy plants were identified by chromosome courts. The results showed that tetraploid plants of L. ruthenicum were successfully induced with 300 mg/L of colchicine solution after 7 and 21 d of induction, with 400 mg/L of colchicine solution after 14 days of induction, and with 500 mg/L of colchicine solution after 7 days of induction, respectively.
基金financially supported by the National Key Research and Development Program of China (2018YFA0702000)the National Natural Science Foundation of China (NSFC),Beijing Natural Science Foundation (2204089)the Fundamental Research Funds for the Central Universities。
文摘Rechargeable aqueous batteries with high power density and energy density are highly desired for electrochemical energy storage.Despite the recent reports of various cathode materials with ultrahigh pseudocapacitance exceeding3000 F g^(-1)(or 800 mA h g^(-1)),the development of anode materials is relatively insufficient,which limits the whole performance of the devices far from practical applications.Herein,we report the preparation of mesoporous Fe_(3)O_(4)@C nanoarrays as high-performance anode for rechargeable Ni/Fe battery by a self-generated sacrificial template method.Zn O/Fe_(3)O_(4)composite was first synthesized by a co-deposition process,and Zn O was subsequently removed by alkali etching to construct the mesoporous structure.A thin carbon film was introduced onto the surface of the electrode by the carbonization of glucose to increase the structural stability of the electrode.The unique mesoporous nanoarray architecture endows the electrode with larger specific surface area,faster charge/mass transport and higher utilization of Fe_(3)O_(4),which shows an ultrahigh specific capacity (292.4 mA h g^(-1)at a current density of 5 mA cm^(-2)) and superior stability in aqueous electrolyte (capacitance retention of 90.8%after 5000cycles).After assembled with hierarchical mesoporous Ni O nanoarray as a cathode,an optimized rechargeable Ni/Fe battery with double mesoporous nanoarray electrodes was fabricated,which provided high energy/power densities(213.3 W h kg^(-1)at 0.658 kW kg^(-1)and 20.7 kW kg^(-1)at113.9 W h kg^(-1),based on the total mass of the active materials)in the potential window of 1.5 V with excellent cyclability(81.7%retention after 5000 charge/discharge cycles).
基金This work was supported by the National Natural Science Foundation of China(21805219,51521001)the National Key Research and Development Program of China(2016YFA0202603)+1 种基金the Program of Introducing Talents of Discipline to Universities(B17034)the Yellow Crane Talent(Science&Technology)Program of Wuhan City.
文摘Niobium pentoxide;Ion and electron transport;Mass loading;Areal capacity;Lithium-ion batteryNiobium pentoxide(Nb2 O5) has attracted great attention as an anode for lithium-ion battery, which is attributed to the high-rate and good stability performances. In this work, TT-, T-, M-, and H-Nb2 O5 microspheres were synthesized by a facile one-step thermal oxidation method. Ion and electron transport properties of Nb2 O5 with different phases were investigated by both electrochemical analyses and density functional theoretical calculations. Without nanostructuring and carbon modification, the tetragonal Nb2 O5(M-Nb2 O5) displays preferable rate capability(121 m Ah g^-1 at 5 A g^-1), enhanced reversible capacity(163 m Ah g^-1 at 0.2 A g^-1) and better cycling stability(82.3% capacity retention after 1000 cycles)when compared with TT-, T-, and H-Nb2 O5. Electrochemical analyses further reveal the diffusioncontrolled Li+intercalation kinetics and in-situ X-ray diffraction analysis indicates superior structural stability upon Li+intercalation/deintercalation. Benefiting from the intrinsic fast ion/electron transport, a high areal capacity of 2.24 m Ah cm^-2 is obtained even at an ultrahigh mass loading of 22.51 mg cm^-2.This work can promote the development of Nb2 O5 materials for high areal capacity and stable lithium storage towards practical applications.
基金supported by the National Natural Science Foundation of China (51932011, 51972346, 51802356, and 51872334)Innovation-Driven Project of Central South University (2020CX024)the Fundamental Research Funds for the Central Universities of Central South University (2020zzts075)。
文摘Potassium-ion batteries(PIBs) hold great potential as an alternative to lithium-ion batteries due to the abundant reserves of potassium and similar redox potentials of K+/K and Li+/Li. Unfortunately, PIBs with carbonaceous electrodes present sluggish kinetics, resulting in unsatisfactory cycling stability and poor rate capability. Herein, we demonstrate that the synergistic effects of the enlarged interlayer spacing and enhanced capacitive behavior induced by the co-doping of nitrogen and sulfur atoms into a carbon structure(NSC) can improve its potassium storage capability. Based on the capacitive contribution calculations, electrochemical impedance spectroscopy, the galvanostatic intermittent titration technique, and density functional theory results, the NSC electrode is found to exhibit favorable electronic conductivity,enhanced capacitive adsorption behavior, and fast K+ ion diffusion kinetics. Additionally, a series of exsitu characterizations demonstrate that NSC exhibits superior structural stability during the(de)potassiation process. As a result, NSC displays a high reversible capacity of 302.8 mAh g-1 at 0.1 Ag-1 and a stable capacity of 105.2 m Ahg-1 even at 2 Ag-1 after 600 cycles. This work may offer new insight into the effects of the heteroatom doping of carbon materials on their potassium storage properties and facilitate their application in PIBs.
基金financially supported by the National Natural Science Foundation of China(21371023)
文摘Hierarchical flower-structured two-dimensional(2 D)nanosheet is favorable for electrochemical reactions.The unique structure not only exposes the maximized active sites and shortens ion/electron diffusion channels,but also inhibits the structural strain during cycling processes.Herein,we report the hierarchical flower-like pure spinel manganese-based oxide nanosheets synthesized via a template-orientated strategy.The oriented template is fabricated by decomposition of carbonate obtained from"bubble reaction",via an alcoholassisted hydrothermal process.The resultant spinel manganese-based oxide nanosheets simultaneously possess excellent rate capability and cycling stability.The high-voltage LiNi0.5Mn1.5O4(LNMO-HF)has a uniform phase distribution without the common impurity phase LixNi1-xO2 and NixO.Besides,the LNMO-HF delivers high discharge capacity of142.6 mA h g-with specific energy density of 660.7 W h kg 1 at 1 C under 55℃.More importantly,the template-orientated strategy can be extended to the synthesis of LiMn2 O4(LMO),which can achieve 88.12%capacity retention after 1000 cycles.
基金supported by the National Natural Science Foundation of China (51601127, 21603162 and 51671145)China Post-doctoral Science Fund (2015M581304)+1 种基金Tianjin Municipal Education Commission, Tianjin Municipal Science and Technology Commission (16ZXCLGX00120)the Fundamental Research Funds of Tianjin University of Technology
文摘Li-ion hybrid supercapacitors （Li-HECs） facilitate effective combination of the advantages of supercapacitors and Li-ion batteries （LIBs）. However, challenges remain in designing and preparing suitable anode and cathode materials, which often require tedious and expensive procedures. Herein, we demonstrated that hollow N-doped carbon capsules （HNC） with and without a Fe304 nanoparticle core can respectively function as the anode and the cathode in very-high-performance Li-HECs. The Fe3Oa@NC anode exhibited a high reversible specific capacity exceeding 1530 mA h g^-1 at 100 mA g^-1 and excellent rate capability （45% capacity retention from 0.1 to 5 A g^-1） and cycle stability （〉97% retention after 100 cycles）. Moreover, high rate performance was achieved in a full-cell using the HNC cathode. By combining the respective structural advantages of the components, the hybrid device with Fe3Oa@NC//HN C exhibited a remark- able energy density of 185 W h kg^-1 at a power density of 39 W kg^-1. The hybrid device furnished a battery-inaccessible power density of 28 kW kg^-1 with rapid charging/discharging within 9 s at an energy density of 95 W h kg^-1.
