Activated carbon was fabricated by using oil asphalt as carbon source, KOH as activator. The samples were analyzed by N2 adsorption, scanning electron microscopy （SEM）. Cyclic voltammetry and galvanostatic charge-di...Activated carbon was fabricated by using oil asphalt as carbon source, KOH as activator. The samples were analyzed by N2 adsorption, scanning electron microscopy （SEM）. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical performance of the samples. The results showed that the pore size was mainly in the range of 0.5-9.0 nm. Supercapacitors based on the sample AC （Activated carbon） have low ESR and excellent power property.展开更多
A high-performance porous carbon material for supercapacitor electrodes was prepared by using a polymer blend method. Phenol-formaldehyde resin and gelatin were used as carbon precursor polymer and pore former polymer...A high-performance porous carbon material for supercapacitor electrodes was prepared by using a polymer blend method. Phenol-formaldehyde resin and gelatin were used as carbon precursor polymer and pore former polymer, respectively. The blends were carbonized at 800℃ in nitrogen. SEM, BET measurement and BJH method reveal that the obtained carbon possesses a mesoporous characteristic, with the average pore size between 3.0 nm and 5.0 nm. The electrochemical properties of supercapacitor using these carbons as electrode material were investigated by cyclic voltammetry and constant current charge-discharge. The results indicate that the composition of blended polymers has a strong effect on the specific capacitance. When the mass ratio of PF to gelatin is kept at 1：1, the largest surface area of 222 m2/g is obtained, and the specific capacitance reaches 161 F/g.展开更多
Activated carbon （AC） was fabricated by Coconut shell as carbon source, KOH as activator. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical performance of the sample...Activated carbon （AC） was fabricated by Coconut shell as carbon source, KOH as activator. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical performance of the samples. The results showed that： Supercapacitors based on the sample AC-3 have low Equivalent series resistanceb （ESR） and excellent power property.展开更多
Activated carbon （AC） was fabricated by using phenolic resin as carbon source, silica gel as inorganic template, KOH as activator. The samples were analyzed by N2 adsorption, scanning electron microscopy （SEM）. Cy...Activated carbon （AC） was fabricated by using phenolic resin as carbon source, silica gel as inorganic template, KOH as activator. The samples were analyzed by N2 adsorption, scanning electron microscopy （SEM）. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical performance of the samples. The results showed that the pore size was mainly in the range of 0.5 9.0 nm. Supercapacitors based on the sample AC-3 have low equivalent series resistanceb （ESR） and excellent power property.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
Tin-based nanomaterials have been extensively explored as high-capacity anode materials for lithium ion batteries（LIBs）. However,the large volume changes upon repeated cycling always cause the pulverization of the e...Tin-based nanomaterials have been extensively explored as high-capacity anode materials for lithium ion batteries（LIBs）. However,the large volume changes upon repeated cycling always cause the pulverization of the electrode materials. Herein,we report the fabrication of uniform SnS_2@C hollow microspheres from hydrothermally prepared SnO_2@C hollow microspheres by a solid-state sulfurization process. The as-prepared hollow SnS_2@C microspheres with unique carbon shell,as electrodes in LIBs,exhibit high reversible capacity of 814 mA h g^（-1） at a current density of 100 mA g^（-1）,good cycling performance（783 mA h g^（-1） for 200 cycles maintained with an average degradation rate of 0.02% per cycle） and remarkable rate capability（reversible capabilities of 433 mA h g^（-1）at 2C）. The hollow space could serve as extra space for volume expansion during the charge-discharge cycling,while the carbon shell can ensure the structural integrity of the microspheres. The preeminent electrochemical performances of the SnS_2@C electrodes demonstrate their promising application as anode materials in the next-generation LIBs.展开更多
Transition-metal compounds have received extensive attention from researchers due to their high reversible capacity and suitable voltage platform as potassium-ion battery anodes.However,these materials commonly featur...Transition-metal compounds have received extensive attention from researchers due to their high reversible capacity and suitable voltage platform as potassium-ion battery anodes.However,these materials commonly feature a poor conductivity and a large volume expansion,thus leading to underdeveloped rate capability and cyclic stability.Herein,we successfully encapsulated ultrafine CoP and CoSb nanoparticles into rich N-doped carbon nanofibers(NCFs)via electrospinning,carbonization,and phosphorization(antimonidization).The N-doped carbon fiber prevents the aggregation of nanoparticles,buffers the volume expansion of CoP and CoSb during charging and discharging,and improves the conductivity of the composite material.As a result,the CoP/NCF anode exhibits excellent potassium-ion storage performance,including an outstanding reversible capacity of 335mAh g^(-1),a decent capacity retention of 79.3%after 1000 cycles at 1Ag^(-1)and a superior rate capability of 148mAh g^(-1)at 5Ag^(-1),superior to most of the reported transition-metalbased potassium-ion battery anode materials.展开更多
The high-temperature sodium-ion batteries(SIBs)used for large-scale energy storage have attracted extensive attention in recent years.However,the development of SIBs is still hampered mainly by their poor charge/disch...The high-temperature sodium-ion batteries(SIBs)used for large-scale energy storage have attracted extensive attention in recent years.However,the development of SIBs is still hampered mainly by their poor charge/discharge efficiency and stability,necessitating the search for appropriate electrodes.A simple potassium ion intercalation process is used herein to obtain the potassium vanadate(KV_(3)O_(8))nanobelts.When serving as the anode for SIBs at a high temperature(60℃),the KV_(3)O_(8) nanobelts display superior sodium storage performance with a high capacity of 414mA h g^(-1) at 0.1Ag^(-1),remarkable rate capability(220mAh g^(-1) at 20Ag^(-1)),and super-long cycle life(almost no capacity fading at 10Ag^(-1) over 1000 cycles).Moreover,the ex-situ X-ray powder diffraction reveals no structural changes throughout the whole charge/discharge process,which further confirms their outstanding stability,indicating KV_(3)O_(8) nanobelts are a promising candidate for high-temperature SIBs.展开更多
文摘Activated carbon was fabricated by using oil asphalt as carbon source, KOH as activator. The samples were analyzed by N2 adsorption, scanning electron microscopy （SEM）. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical performance of the samples. The results showed that the pore size was mainly in the range of 0.5-9.0 nm. Supercapacitors based on the sample AC （Activated carbon） have low ESR and excellent power property.
基金Projects(50772033,50972043) supported by the National Natural Science Foundation of ChinaProject(09JJ3095) supported by the Natural Science Foundation of Hunan Province,China+2 种基金Project(09A001) supported by the Scientific Research Fund of Hunan Provincial Education Department,ChinaProject(2010FJ3151) supported by the Science and Research Plan of Hunan Province,ChinaProject supported by the Science and Technology Innovative Research Team in Higher Education Institution of Hunan Province,China
文摘A high-performance porous carbon material for supercapacitor electrodes was prepared by using a polymer blend method. Phenol-formaldehyde resin and gelatin were used as carbon precursor polymer and pore former polymer, respectively. The blends were carbonized at 800℃ in nitrogen. SEM, BET measurement and BJH method reveal that the obtained carbon possesses a mesoporous characteristic, with the average pore size between 3.0 nm and 5.0 nm. The electrochemical properties of supercapacitor using these carbons as electrode material were investigated by cyclic voltammetry and constant current charge-discharge. The results indicate that the composition of blended polymers has a strong effect on the specific capacitance. When the mass ratio of PF to gelatin is kept at 1：1, the largest surface area of 222 m2/g is obtained, and the specific capacitance reaches 161 F/g.
文摘Activated carbon （AC） was fabricated by Coconut shell as carbon source, KOH as activator. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical performance of the samples. The results showed that： Supercapacitors based on the sample AC-3 have low Equivalent series resistanceb （ESR） and excellent power property.
文摘Activated carbon （AC） was fabricated by using phenolic resin as carbon source, silica gel as inorganic template, KOH as activator. The samples were analyzed by N2 adsorption, scanning electron microscopy （SEM）. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical performance of the samples. The results showed that the pore size was mainly in the range of 0.5 9.0 nm. Supercapacitors based on the sample AC-3 have low equivalent series resistanceb （ESR） and excellent power property.
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 (51302323)the Program for New Century Excellent Talents in University (NCET-13-0594)the Innovationdriven Project of Central South University (2017CX001)
文摘Tin-based nanomaterials have been extensively explored as high-capacity anode materials for lithium ion batteries（LIBs）. However,the large volume changes upon repeated cycling always cause the pulverization of the electrode materials. Herein,we report the fabrication of uniform SnS_2@C hollow microspheres from hydrothermally prepared SnO_2@C hollow microspheres by a solid-state sulfurization process. The as-prepared hollow SnS_2@C microspheres with unique carbon shell,as electrodes in LIBs,exhibit high reversible capacity of 814 mA h g^（-1） at a current density of 100 mA g^（-1）,good cycling performance（783 mA h g^（-1） for 200 cycles maintained with an average degradation rate of 0.02% per cycle） and remarkable rate capability（reversible capabilities of 433 mA h g^（-1）at 2C）. The hollow space could serve as extra space for volume expansion during the charge-discharge cycling,while the carbon shell can ensure the structural integrity of the microspheres. The preeminent electrochemical performances of the SnS_2@C electrodes demonstrate their promising application as anode materials in the next-generation LIBs.
基金financially supported by the National Natural Science Foundation of China(22075147)the Natural Science Foundation of Jiangsu Province(BK20180086).
文摘Transition-metal compounds have received extensive attention from researchers due to their high reversible capacity and suitable voltage platform as potassium-ion battery anodes.However,these materials commonly feature a poor conductivity and a large volume expansion,thus leading to underdeveloped rate capability and cyclic stability.Herein,we successfully encapsulated ultrafine CoP and CoSb nanoparticles into rich N-doped carbon nanofibers(NCFs)via electrospinning,carbonization,and phosphorization(antimonidization).The N-doped carbon fiber prevents the aggregation of nanoparticles,buffers the volume expansion of CoP and CoSb during charging and discharging,and improves the conductivity of the composite material.As a result,the CoP/NCF anode exhibits excellent potassium-ion storage performance,including an outstanding reversible capacity of 335mAh g^(-1),a decent capacity retention of 79.3%after 1000 cycles at 1Ag^(-1)and a superior rate capability of 148mAh g^(-1)at 5Ag^(-1),superior to most of the reported transition-metalbased potassium-ion battery anode materials.
基金supported by the National Natural Science Foundation of China(51801030,51902032,51802044,51902062,and 51802043)the Natural Science Foundation of Jiangsu Province(BK20191026)Guangdong Natural Science Funds for the Distinguished Young Scholar(2019B151502039)。
文摘The high-temperature sodium-ion batteries(SIBs)used for large-scale energy storage have attracted extensive attention in recent years.However,the development of SIBs is still hampered mainly by their poor charge/discharge efficiency and stability,necessitating the search for appropriate electrodes.A simple potassium ion intercalation process is used herein to obtain the potassium vanadate(KV_(3)O_(8))nanobelts.When serving as the anode for SIBs at a high temperature(60℃),the KV_(3)O_(8) nanobelts display superior sodium storage performance with a high capacity of 414mA h g^(-1) at 0.1Ag^(-1),remarkable rate capability(220mAh g^(-1) at 20Ag^(-1)),and super-long cycle life(almost no capacity fading at 10Ag^(-1) over 1000 cycles).Moreover,the ex-situ X-ray powder diffraction reveals no structural changes throughout the whole charge/discharge process,which further confirms their outstanding stability,indicating KV_(3)O_(8) nanobelts are a promising candidate for high-temperature SIBs.
