Surface carboxyl groups enhance the capacities of carbonaceous oxygen electrodes for aprotic lithiumoxygen batteries: A direct observation on binder-free electrodes  

作　　者：Ming Li Liang Xiao Duo Wang Haoyang Dong Bohua Deng Jinping Liu 

机构地区：[1]School of Chemistry,Chemical Engineering and Life Science,Wuhan University of Technology,Wuhan 430070,China [2]State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,Wuhan University of Technology,Wuhan 430070,China

出　　处：《Chinese Chemical Letters》2019年第12期2328-2332,共5页中国化学快报（英文版）

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);the Research Start-Up Fund from Wuhan University of Technology;the Fundamental Research Funds for the Central Universities (WUT:Nos.2019IB003,2016IVA083)

摘　　要：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.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/cm2 of pristine carbon cloth to 1.23 mAh/cm2 of CACC.This work presents an effective way to further optimize the carbonaceous oxygen electrodes via surface functional group engineering

关 键 词：Surface functional group Chemically activated carbon cloth Carbonaceous oxygen electrode Specific discharge capacity Lithium-oxygen battery 

分 类 号：TM911.41[电气工程—电力电子与电力传动] TB383.4[一般工业技术—材料科学与工程]