LithiumvanadatesLiV_(3)O_(8)-LiV_(6)O_(15)(LVO)witha heterojunction structure are synthesized using a conventional high-temperature solid-state method to address the challenges of low ionic conductivity,rapid capacity...LithiumvanadatesLiV_(3)O_(8)-LiV_(6)O_(15)(LVO)witha heterojunction structure are synthesized using a conventional high-temperature solid-state method to address the challenges of low ionic conductivity,rapid capacity decay,and poor cycling performance in conventional lithium-ion battery cathode materials.The charge-discharge processes of LVO span multiple platforms,delivering an impressive specific discharge capacity of 219.4 mAh.g^(-1) at 1C.Remarkably,LVO exhibits a high-capacity retention rate of 81.3%after 800 cycles within the typical operating voltage range of lithium-ion batteries(2.8-4.3V).Rate capability tests and electrochemical impedance spectroscopy(EIS)reveal that,compared to traditional cathode materials,LVO significantly enhances Li*diffusion rates(D_(Li*))and reduces charge transfer resistance(Ret).展开更多
In order to achieve the high capacities of carbonaceous oxygen diffusion electrodes for aprotic lithiumoxygen batteries(Li-O2 batteries),most efforts currently focus on the design of rational porous architectures.Only...In order to achieve the high capacities of carbonaceous oxygen diffusion electrodes for aprotic lithiumoxygen batteries(Li-O2 batteries),most efforts currently focus on the design of rational porous architectures.Only few works study the surface chemistry effect that might be a critical factor influencing the capacities of carbonaceous electrodes.In addition,the surface chemistry effect is very difficult to be studied in composite electrodes due to the influences of binders and additives.Herein,we propose chemically activated carbon cloth(CACC) as an ideal model to investigate the effect of surface functional groups on the discharge capacities of carbonaceous oxygen electrodes for Li-O2 batteries.The intrinsic surface chemistry effect on the performance of carbonaceous cathode is directly observed for the first time without the influences of binders and additives.Results indicate that the surface carboxyl groups introduced by the chemical treatment not only function as the appropriate nucleation sites for Li2 O2 but also induce the formation of toroid-like Li2 O2.Thus,the surface carboxyl modification enhances the discharge capacities from 0.48 mAh/cm^2 of pristine carbon cloth to 1.23 mAh/cm^2 of CACC.This work presents an effective way to further optimize the carbonaceous oxygen electrodes via surface functional group engineering.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52125405 and U22A20108)Thailand Science Research and Innovation Fund Chulalongkorn University,National Research Council of Thailand(NRCT)+1 种基金Chulalongkorn University(No.42A660383)the Hub of Talents:Sustainable Materials for Circular Economy,National Research Council of Thailand(NRCT).
文摘LithiumvanadatesLiV_(3)O_(8)-LiV_(6)O_(15)(LVO)witha heterojunction structure are synthesized using a conventional high-temperature solid-state method to address the challenges of low ionic conductivity,rapid capacity decay,and poor cycling performance in conventional lithium-ion battery cathode materials.The charge-discharge processes of LVO span multiple platforms,delivering an impressive specific discharge capacity of 219.4 mAh.g^(-1) at 1C.Remarkably,LVO exhibits a high-capacity retention rate of 81.3%after 800 cycles within the typical operating voltage range of lithium-ion batteries(2.8-4.3V).Rate capability tests and electrochemical impedance spectroscopy(EIS)reveal that,compared to traditional cathode materials,LVO significantly enhances Li*diffusion rates(D_(Li*))and reduces charge transfer resistance(Ret).
基金supported by grants from the National Natural Science Foundation of China (Nos.21673169,51672205)the National Key R&D Program of China (No.2016YFA0202602)+1 种基金the Research Start-Up Fund from Wuhan University of Technologythe Fundamental Research Funds for the Central Universities (WUT:Nos.2019IB003,2016IVA083)
文摘In order to achieve the high capacities of carbonaceous oxygen diffusion electrodes for aprotic lithiumoxygen batteries(Li-O2 batteries),most efforts currently focus on the design of rational porous architectures.Only few works study the surface chemistry effect that might be a critical factor influencing the capacities of carbonaceous electrodes.In addition,the surface chemistry effect is very difficult to be studied in composite electrodes due to the influences of binders and additives.Herein,we propose chemically activated carbon cloth(CACC) as an ideal model to investigate the effect of surface functional groups on the discharge capacities of carbonaceous oxygen electrodes for Li-O2 batteries.The intrinsic surface chemistry effect on the performance of carbonaceous cathode is directly observed for the first time without the influences of binders and additives.Results indicate that the surface carboxyl groups introduced by the chemical treatment not only function as the appropriate nucleation sites for Li2 O2 but also induce the formation of toroid-like Li2 O2.Thus,the surface carboxyl modification enhances the discharge capacities from 0.48 mAh/cm^2 of pristine carbon cloth to 1.23 mAh/cm^2 of CACC.This work presents an effective way to further optimize the carbonaceous oxygen electrodes via surface functional group engineering.
