Potassium-ion hybrid capacitors(PIHCs)tactfully combining capacitor-type cathode with battery-type anode have recently attracted increasing attentions due to their advantages of decent energy density,high power densit...Potassium-ion hybrid capacitors(PIHCs)tactfully combining capacitor-type cathode with battery-type anode have recently attracted increasing attentions due to their advantages of decent energy density,high power density,and low cost;the mismatches of capacity and kinetics between capacitor-type cathode and battery-type anode in PIHCs yet hinder their overall performance output.Herein,based on prediction of density functional theory calculations,we find Se/N co-doped porous carbon is a promising candidate for K+storage and thus develop a simple and universal self-sacrifice template method to fabricate Se and N co-doped three-dimensional(3D)macroporous carbon(Se/N-3DMpC),which features favorable properties of connective hier-archical pores,expanded interlayer structure,and rich activity site for boosting pseudocapacitive activity and kinetics toward K^(+)storage anode and enhancing capacitance performance for the reversible anion adsorption/desorption cath-ode.As expected,the as-assembled PIHCs full cell with a working voltage as high as 4.0 V delivers a high energy density of 186 Wh kg^(−1) and a power output of 8100 W kg^(−1) as well as excellent long service life.The proof-of-concept PIHCs with excellent performance open a new avenue for the development and application of high-performance hybrid capacitors.展开更多
The desire for practical utilization of rechargeable lithium batteries with high energy density has motivated attempts to develop new electrode materials and battery systems. Here, without additional binders we presen...The desire for practical utilization of rechargeable lithium batteries with high energy density has motivated attempts to develop new electrode materials and battery systems. Here, without additional binders we present a simple vacuum filtration method to synthesize nitrogen and sulfur codoped graphene(N,S-G) blocking layer, which is ultra-lightweight, conductive, and free standing. When the N,S-G membrane was inserted between the catholyte and separator, the lithium–selenium(Li–Se)batteries exhibited a high reversible discharge capacity of 330.7 mAh g^(-1) at 1 C(1 C = 675 mA g^(-1)) after 500 cycles and high rate performance(over 310 mAh g^(-1) at 4 C) even at an active material loading as high as ～5 mg cm^(-2). This excellent performance can be ascribed to homogenous dispersion of the liquid active material in the electrode, good Li^+-ion conductivity, fast electronic transport in the conductive graphene framework, andstrong chemical confinement of polyselenides by nitrogen and sulfur atoms. More importantly, it is a promising strategy for enhancing the energy density of Li–Se batteries by using the catholyte with a lightweight heteroatom doping carbon matrix.展开更多
基金This work was supported by the National Natural Science Foundation of China(Project No.21875253)CAS-Commonwealth Scientific and Industrial Research Organization(CSIRO)Joint Research Projects(121835KYSB20200039)Scientific Research and Equipment Development Project of CAS(YJKYYQ20190007).
文摘Potassium-ion hybrid capacitors(PIHCs)tactfully combining capacitor-type cathode with battery-type anode have recently attracted increasing attentions due to their advantages of decent energy density,high power density,and low cost;the mismatches of capacity and kinetics between capacitor-type cathode and battery-type anode in PIHCs yet hinder their overall performance output.Herein,based on prediction of density functional theory calculations,we find Se/N co-doped porous carbon is a promising candidate for K+storage and thus develop a simple and universal self-sacrifice template method to fabricate Se and N co-doped three-dimensional(3D)macroporous carbon(Se/N-3DMpC),which features favorable properties of connective hier-archical pores,expanded interlayer structure,and rich activity site for boosting pseudocapacitive activity and kinetics toward K^(+)storage anode and enhancing capacitance performance for the reversible anion adsorption/desorption cath-ode.As expected,the as-assembled PIHCs full cell with a working voltage as high as 4.0 V delivers a high energy density of 186 Wh kg^(−1) and a power output of 8100 W kg^(−1) as well as excellent long service life.The proof-of-concept PIHCs with excellent performance open a new avenue for the development and application of high-performance hybrid capacitors.
基金supported by the National Natural Science Foundation of China (51125001,51172005)the NSFCRGC Joint Research Scheme (51361165201)the Start-up Foundation of High-level Talents in Chongqing Technology and Business University (1856008)
文摘The desire for practical utilization of rechargeable lithium batteries with high energy density has motivated attempts to develop new electrode materials and battery systems. Here, without additional binders we present a simple vacuum filtration method to synthesize nitrogen and sulfur codoped graphene(N,S-G) blocking layer, which is ultra-lightweight, conductive, and free standing. When the N,S-G membrane was inserted between the catholyte and separator, the lithium–selenium(Li–Se)batteries exhibited a high reversible discharge capacity of 330.7 mAh g^(-1) at 1 C(1 C = 675 mA g^(-1)) after 500 cycles and high rate performance(over 310 mAh g^(-1) at 4 C) even at an active material loading as high as ～5 mg cm^(-2). This excellent performance can be ascribed to homogenous dispersion of the liquid active material in the electrode, good Li^+-ion conductivity, fast electronic transport in the conductive graphene framework, andstrong chemical confinement of polyselenides by nitrogen and sulfur atoms. More importantly, it is a promising strategy for enhancing the energy density of Li–Se batteries by using the catholyte with a lightweight heteroatom doping carbon matrix.
