摘要
Although the fast development of potassium-ion hybrid capacitors(PIHC)recently,the issues such as the slow kinetics and poor durability of potassium ion hosts greatly restric their applications.Herein,a freestanding fiber(NHF fiber)with necklace-like configuration and CoPSe@N-doped carbon(CoPSe@NCNT)heterostructured units is introduced as the anode in PIHC.The highly porous network of NHF fiber facilitates the fast ion transports and promises the good high-rate property.Additionally,the nanoscle crystallites inside in-situ grown NCNT favor the high adaption to volume expansion/shrinkage and endow good structure stability during ion insertion/deinsertion.Density function theoretical(DFT)calculations disclose the CoPSe@NCNT heterostructure has improved intrinsic conductivity,fast potassium migration,and decreased energy barrier.Meanwhile,the finite element simulation analysis(FEA)reveals the decreased stress inside the NHF architecture during charge/discharge processes.Moreover,the electrochemical tests confirm the fast and durable properties of the CoPSe@NCNT NHF fibers for potassium storage.Furthermore,the PIHC full cell with the anode of CoPSe@NCNT NHF fiber is assembled,which obtains the superior energy/power densities and high capacity retention(89%)after 2000 cycles at 2 A g^(-1).When the polymer electrolyte is incooperated,the flexible PIHC device achieves the good pliability and good adaptation during wide temperature changes from-20 to 25℃.Therefore,this work introduces a novel anode for fast potassium ion storage,and opens a new approach to assemble the power sources for flexible electronics in diverse conditions.
