The passivation of non-radiative states and inhibition of band tailings are desirable for improving the open-circuit voltage(V_(oc))of CZTSSe thin-film solar cells.Recently,alkali metal doping has been investigated to...The passivation of non-radiative states and inhibition of band tailings are desirable for improving the open-circuit voltage(V_(oc))of CZTSSe thin-film solar cells.Recently,alkali metal doping has been investigated to passivate defects in CZTSSe films.Herein,we investigate Li doping effects by applying Li OH into CZTSSe precursor solutions,and verify that carrier transport is enhanced in the CZTSSe solar cells.Systematic characterizations demonstrate that Li doping can effectively passivate non-radiative recombination centers and reduce band tailings of the CZTSSe films,leading to the decrease in total defect density and the increase in separation distance between donor and acceptor.Fewer free carriers are trapped in the band tail states,which speeds up carrier transport and reduces the probability of deep-level defects capturing carriers.The charge recombination lifetime is about twice as long as that of the undoped CZTSSe device,implying the heterojunction interface recombination is also inhibited.Besides,Li doping can increase carrier concentration and enhance build-in voltage,leading to a better carrier collection.By adjusting the Li/(Li+Cu)ratio to 18%,the solar cell efficiency is increased significantly to 9.68%with the fill factor(FF)of 65.94%,which is the highest FF reported so far for the flexible CZTSSe solar cells.The increased efficiency is mainly attributed to the reduction of V_(oc)deficit and the improved CZTSSe/Cd S junction quality.These results open up a simple route to passivate non-radiative states and reduce the band tailings of the CZTSSe films and improve the efficiency of the flexible CZTSSe solar cells.展开更多
The lithium(Li)metal anode is widely regarded as an ideal anode material for high-energy-density batteries.However,uncontrolled Li dendrite growth often leads to unfavorable interfaces and low Coulombic efficiency(CE)...The lithium(Li)metal anode is widely regarded as an ideal anode material for high-energy-density batteries.However,uncontrolled Li dendrite growth often leads to unfavorable interfaces and low Coulombic efficiency(CE),limiting its broader application.Herein,an ether-based electrolyte(termed FGN-182)is formulated,exhibiting ultra-stable Li metal anodes through the incorporation of LiFSI and LiNO3 as dual salts.The synergistic effect of the dual salts facilitates the formation of a highly robust SEI film with fast Li+transport kinetics.Notably,Li||Cu half cells exhibit an average CE reaching up to 99.56%.In particular,pouch cells equipped with high-loading lithium cobalt oxide(LCO,3 mAh cm^(-2))cathodes,ultrathin Li chips(25μm),and lean electrolytes(5 g Ah-1)demonstrate outstanding cycling performance,retaining 80%capacity after 125 cycles.To address the gas issue in the cathode under high voltage,cathode additives 1,3,6-tricyanohexane is incorporated with FGN-182;the resulting high-voltage LCO||Li(4.4 V)pouch cells can cycle steadily over 93 cycles.This study demonstrates that,even with the use of ether-based electrolytes,it is possible to simultaneously achieve significant improvements in both high Li utilization and electrolyte tolerance to high voltage by exploring appropriate functional additives for both the cathode and anode.展开更多
The cathode materials LiNixCo1-xO2 (0≤x≤1) for lithium ion battery were prepared in solid phase . The effects of synthesis temperature , the time of heat treatment and also the ratio of raw materials on products wer...The cathode materials LiNixCo1-xO2 (0≤x≤1) for lithium ion battery were prepared in solid phase . The effects of synthesis temperature , the time of heat treatment and also the ratio of raw materials on products were discussed . The residts showed that the products preheated under 600℃ and then sintered under constant, temperature 75017 were better than those sintered under constant temperature 650℃ or 850℃ , and their layer structures were more obvious and their initial capacity was higher . The longer the heat-treating time is , the stronger the products ’ XRD peaks intensity and the better their structures and electrochemical performance are. The samples LiN-ix Co 1-xO2(0≤x≤1) with a perfect structure and electrochemical performance were synthesized. And the products initial capacity was perfect when n(Li) : n( Ni) : n( Co) ℃ 1.15:0.3:0.7,viz. 156.l46mAh/g.展开更多
基金Project(2018RS3091) supported by the Hunan Innovation Team,ChinaProjects(52202308, 12105097) supported by the National Natural Science Foundation of ChinaProject(2021RC2092) supported by the Science and Technology Innovation Program of Hunan Province,China。
基金supported by the National Natural Science Foundation of China(62074037,52002073)the Science and Technology Department of Fujian Province(2020I0006)+3 种基金the Natural Science Foundation of Fujian Province(2019J01218)the Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZZ124)the Education and Scientific Research Project of Fujian Province(JAT200372)the Scientific Research Project of Fujian Jiangxia University(JXZ2019006)。
文摘The passivation of non-radiative states and inhibition of band tailings are desirable for improving the open-circuit voltage(V_(oc))of CZTSSe thin-film solar cells.Recently,alkali metal doping has been investigated to passivate defects in CZTSSe films.Herein,we investigate Li doping effects by applying Li OH into CZTSSe precursor solutions,and verify that carrier transport is enhanced in the CZTSSe solar cells.Systematic characterizations demonstrate that Li doping can effectively passivate non-radiative recombination centers and reduce band tailings of the CZTSSe films,leading to the decrease in total defect density and the increase in separation distance between donor and acceptor.Fewer free carriers are trapped in the band tail states,which speeds up carrier transport and reduces the probability of deep-level defects capturing carriers.The charge recombination lifetime is about twice as long as that of the undoped CZTSSe device,implying the heterojunction interface recombination is also inhibited.Besides,Li doping can increase carrier concentration and enhance build-in voltage,leading to a better carrier collection.By adjusting the Li/(Li+Cu)ratio to 18%,the solar cell efficiency is increased significantly to 9.68%with the fill factor(FF)of 65.94%,which is the highest FF reported so far for the flexible CZTSSe solar cells.The increased efficiency is mainly attributed to the reduction of V_(oc)deficit and the improved CZTSSe/Cd S junction quality.These results open up a simple route to passivate non-radiative states and reduce the band tailings of the CZTSSe films and improve the efficiency of the flexible CZTSSe solar cells.
基金supported by the National Key Research and Development Program of China(2022YFB2502103)the Xiamen Science and Technology Project(3502Z20231057)+1 种基金the National Natural Science Foundation of China(Nos.22279107 and 22288102)J.You,R.Wei,and L.Niu acknowledge the China Scholarship Council(CSC)for a doctoral scholarship(Grant Nos.202006310030,202108530138,and 202108530139).
文摘The lithium(Li)metal anode is widely regarded as an ideal anode material for high-energy-density batteries.However,uncontrolled Li dendrite growth often leads to unfavorable interfaces and low Coulombic efficiency(CE),limiting its broader application.Herein,an ether-based electrolyte(termed FGN-182)is formulated,exhibiting ultra-stable Li metal anodes through the incorporation of LiFSI and LiNO3 as dual salts.The synergistic effect of the dual salts facilitates the formation of a highly robust SEI film with fast Li+transport kinetics.Notably,Li||Cu half cells exhibit an average CE reaching up to 99.56%.In particular,pouch cells equipped with high-loading lithium cobalt oxide(LCO,3 mAh cm^(-2))cathodes,ultrathin Li chips(25μm),and lean electrolytes(5 g Ah-1)demonstrate outstanding cycling performance,retaining 80%capacity after 125 cycles.To address the gas issue in the cathode under high voltage,cathode additives 1,3,6-tricyanohexane is incorporated with FGN-182;the resulting high-voltage LCO||Li(4.4 V)pouch cells can cycle steadily over 93 cycles.This study demonstrates that,even with the use of ether-based electrolytes,it is possible to simultaneously achieve significant improvements in both high Li utilization and electrolyte tolerance to high voltage by exploring appropriate functional additives for both the cathode and anode.
基金Funded by the National Science Foundation of China (No. 50062001)
文摘The cathode materials LiNixCo1-xO2 (0≤x≤1) for lithium ion battery were prepared in solid phase . The effects of synthesis temperature , the time of heat treatment and also the ratio of raw materials on products were discussed . The residts showed that the products preheated under 600℃ and then sintered under constant, temperature 75017 were better than those sintered under constant temperature 650℃ or 850℃ , and their layer structures were more obvious and their initial capacity was higher . The longer the heat-treating time is , the stronger the products ’ XRD peaks intensity and the better their structures and electrochemical performance are. The samples LiN-ix Co 1-xO2(0≤x≤1) with a perfect structure and electrochemical performance were synthesized. And the products initial capacity was perfect when n(Li) : n( Ni) : n( Co) ℃ 1.15:0.3:0.7,viz. 156.l46mAh/g.
