Potassium-ion hybrid capacitors(PIHCs)reconcile the advantages of batteries and supercapacitors,exhibiting both good energy density and high-power density.However,the low-rate performance and poor cycle stability of b...Potassium-ion hybrid capacitors(PIHCs)reconcile the advantages of batteries and supercapacitors,exhibiting both good energy density and high-power density.However,the low-rate performance and poor cycle stability of battery-type anodes hinder their practical application.Herein,phosphorus/nitrogen co-doped hollow carbon fibers(P-HCNFs)are prepared by a facile template method.The stable grape-like structure with continuous and interconnected cavity structure is an ideal scaffold for shortening the ion transport and relieving volume expansion,while the introduction of P atoms and intrinsic N atoms can create abundant extrinsic/intrinsic defects and additional active sites,reducing the K+diffusion barrier and improving the capacitive-controlled capacity.The P-HCNFs delivers a high specific capacity of 310 mAh·g^(-1)at 0.1 A·g^(-1)with remarkable ultra-high-rate performance(140 mAh·g^(-1)at 50 A·g^(-1))and retains an impressive capacity retention of 87%after 10,000 cycles at 10 A·g^(-1).As expected,the as-assembled PIHCs present a high energy density(115.8 Wh·kg^(-1)at 378.0 W·kg^(-1))and excellent capacity retention of 91%after 20,000 cycles.This work not only shows great potential for utilizing heteroatom-doping and structural design strategies to boost potassium storage,but also paves the way for advancing the practicality of high-energy PIHCs devices.展开更多
Potassium ion hybrid capacitors(PIHC)have promising applications in medium and large-scale energy storage systems due to their high energy/power density,abundant potassium resource and low cost.However,the slow kineti...Potassium ion hybrid capacitors(PIHC)have promising applications in medium and large-scale energy storage systems due to their high energy/power density,abundant potassium resource and low cost.However,the slow kinetics of battery-type anodes originating from the large-size K+results in a mismatch between the two electrodes,rendering the modest energy density of PIHC.Herein,we first develop an electrospinning strategy to successfully synthesize fibrous precursor by using the HNO_(3)pre-oxidized low-softening-point coal pitch as the low-cost raw material.With further carbonization or KOH activation,the two types of carbon nanofibers(CNF)are fabricated as anode and cathode materials,respectively,towards the dual-carbon PIHC devices.Thanks to its threedimensional interconnected porous conducting network and large layer spacing,the resulted CNF anode material is endowed with high reversible capacities,excellent rate and long cycle stability.Meanwhile,the activated CNF cathode with a large surface area of 2169 m^(2)·g^(-1)exhibits excellent capacitive performance.A PIHC constructed with the two fibrous electrodes delivers an energy density of110.0 Wh·kg^(-1)at 200.0 W kg^(-1),along with a capacitance retention of 83.5%after 10,000 cycles at 1.0 A·g^(-1).The contribution here provides a cost-efficiency avenue and platform for advanced dual-carbon PIHC.展开更多
Developing facile and economical strategies to fabricate nitrogen-doped porous carbon anode is desirable for dual-carbon potassium ion hybrid capacitors(PIHCs).Here,a high-concentration edge-nitrogen-doped porous carb...Developing facile and economical strategies to fabricate nitrogen-doped porous carbon anode is desirable for dual-carbon potassium ion hybrid capacitors(PIHCs).Here,a high-concentration edge-nitrogen-doped porous carbon(NPC)anode is synthesized by a template-free strategy,in which the total content of pyrrolic nitrogen and pyridinic nitrogen accounts for more than 80%of the nitrogen atoms.As a result,the NPC anode displays a capacity of 315.4 mA h g^(−1)at a current rate of 0.1 A g^(−1)and 189.1 mA h g^(−1)at 5 A g^(−1).Ex situ characterizations and density functional theory calculations demonstrate the high-concentration edge-nitrogen doping enhances K^(+)adsorption and electronic conductivity of carbon materials,resulting in good electrochemical performance.The assembled NPC//CMK-3 PIHC delivers an energy density of 71.1 W h kg^(−1)at a power density of 771.9 W kg^(−1)over 8,000 cycles.展开更多
基金financially supported by the Youth Innovation Team of Colleges and Universities in Shandong Province(No.2022KJ223)the National Natural Science Foundation of China(Nos.22078179 and 52007110)+1 种基金the Natural Science Foundation of Shandong Province(Nos.ZR2022JQ10 and ZR2021MA026)Taishan S cholar Foundation(No.tsqn201812063)。
文摘Potassium-ion hybrid capacitors(PIHCs)reconcile the advantages of batteries and supercapacitors,exhibiting both good energy density and high-power density.However,the low-rate performance and poor cycle stability of battery-type anodes hinder their practical application.Herein,phosphorus/nitrogen co-doped hollow carbon fibers(P-HCNFs)are prepared by a facile template method.The stable grape-like structure with continuous and interconnected cavity structure is an ideal scaffold for shortening the ion transport and relieving volume expansion,while the introduction of P atoms and intrinsic N atoms can create abundant extrinsic/intrinsic defects and additional active sites,reducing the K+diffusion barrier and improving the capacitive-controlled capacity.The P-HCNFs delivers a high specific capacity of 310 mAh·g^(-1)at 0.1 A·g^(-1)with remarkable ultra-high-rate performance(140 mAh·g^(-1)at 50 A·g^(-1))and retains an impressive capacity retention of 87%after 10,000 cycles at 10 A·g^(-1).As expected,the as-assembled PIHCs present a high energy density(115.8 Wh·kg^(-1)at 378.0 W·kg^(-1))and excellent capacity retention of 91%after 20,000 cycles.This work not only shows great potential for utilizing heteroatom-doping and structural design strategies to boost potassium storage,but also paves the way for advancing the practicality of high-energy PIHCs devices.
基金financially supported by the National Natural Science Foundation of China(Nos.52072151 and 52171211)Taishan Scholars(No.ts201712050)+2 种基金Jinan Independent Innovative Team(No.2020GXRC015)the Natural Science Doctoral Foundation of Shandong Province(No.ZR2019BB057)the Major Program of Shandong Province Natural Science Foundation(No.ZR2021ZD05)。
文摘Potassium ion hybrid capacitors(PIHC)have promising applications in medium and large-scale energy storage systems due to their high energy/power density,abundant potassium resource and low cost.However,the slow kinetics of battery-type anodes originating from the large-size K+results in a mismatch between the two electrodes,rendering the modest energy density of PIHC.Herein,we first develop an electrospinning strategy to successfully synthesize fibrous precursor by using the HNO_(3)pre-oxidized low-softening-point coal pitch as the low-cost raw material.With further carbonization or KOH activation,the two types of carbon nanofibers(CNF)are fabricated as anode and cathode materials,respectively,towards the dual-carbon PIHC devices.Thanks to its threedimensional interconnected porous conducting network and large layer spacing,the resulted CNF anode material is endowed with high reversible capacities,excellent rate and long cycle stability.Meanwhile,the activated CNF cathode with a large surface area of 2169 m^(2)·g^(-1)exhibits excellent capacitive performance.A PIHC constructed with the two fibrous electrodes delivers an energy density of110.0 Wh·kg^(-1)at 200.0 W kg^(-1),along with a capacitance retention of 83.5%after 10,000 cycles at 1.0 A·g^(-1).The contribution here provides a cost-efficiency avenue and platform for advanced dual-carbon PIHC.
基金funding support from the Fundamental Research Funds for the Central Universities(Grants KY2060000150,GG2060127001,and WK2060000040)support from USTC Center for Micro and Nano-scale Research and Fabrication and NEWARE。
文摘Developing facile and economical strategies to fabricate nitrogen-doped porous carbon anode is desirable for dual-carbon potassium ion hybrid capacitors(PIHCs).Here,a high-concentration edge-nitrogen-doped porous carbon(NPC)anode is synthesized by a template-free strategy,in which the total content of pyrrolic nitrogen and pyridinic nitrogen accounts for more than 80%of the nitrogen atoms.As a result,the NPC anode displays a capacity of 315.4 mA h g^(−1)at a current rate of 0.1 A g^(−1)and 189.1 mA h g^(−1)at 5 A g^(−1).Ex situ characterizations and density functional theory calculations demonstrate the high-concentration edge-nitrogen doping enhances K^(+)adsorption and electronic conductivity of carbon materials,resulting in good electrochemical performance.The assembled NPC//CMK-3 PIHC delivers an energy density of 71.1 W h kg^(−1)at a power density of 771.9 W kg^(−1)over 8,000 cycles.
