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
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.
