The designing of reasonable nanocomposite materials and proper introduction of defect engineering are of great significance for the improvement of the poor electronic conductivity and slow reaction kinetics of mangane...The designing of reasonable nanocomposite materials and proper introduction of defect engineering are of great significance for the improvement of the poor electronic conductivity and slow reaction kinetics of manganese-based compounds. Herein, we report manganese-deficient Mn_(3)O_(4) nanoparticles which grow in-situ on highly conductive carbon nanotubes(CNTs)(denoted as DMOC) as an advanced cathode material for aqueous rechargeable zinc-ion batteries(RAZIBs). According to experimental and calculation results, the DMOC cathode integrates the advantages of enriched Mn defects and small particle size. These features not only enhance electronic conductivity but also create more active site and contribute to fast reaction kinetics. Moreover, the structure of DMOC is maintained during the charging and discharging process, thus benefiting for excellent cycle stability. As a result, the DMOC electrode delivers a high specific capacity of 420.6 m A h g^(-1) at 0.1 A g^(-1) and an excellent cycle life of 2800 cycles at 2.0 A g^(-1) with a high-capacity retention of 84.1%. In addition, the soft-packaged battery assembled with DMOC cathode exhibits long cycle life and high energy density of 146.3 Wh kg^(-1) at 1.0 A g^(-1) . The results are beneficial for the development of Zn/Mn_(3)O_(4) battery for practical energy storage.展开更多
A fundamental question in the oxygen reduction reaction(ORR)is how to rationally control the electrocatalytic selectivity for opening a four-electron reaction pathway.However,it still lacks direct experimental evidenc...A fundamental question in the oxygen reduction reaction(ORR)is how to rationally control the electrocatalytic selectivity for opening a four-electron reaction pathway.However,it still lacks direct experimental evidence to understand the reaction mechanism.This work unravels that Ag nanoparticles and carbonizing halloysite nanotubes(CHNTs)can trigger the construction of oxygen defects in the MnO_(2),which contribute to the generation of active sites.The Ag/MnO_(2)-CHNTs delivers a superior activity toward ORR with high onset potential,half-wave potential,diffusion-limited current density,long-term durability and methanol tolerance.More importantly,combined with density functional theory calculations,triggering manganese dioxide defects upon the introduction of Ag nanoparticles and CHNTs can alter the electrocatalytic pathway from a two-electron to a direct four-electron direction for ORR,which is the nature of enhanced ORR activity.Based on the analysis of the results,this finding points out a very effective approach for exploring catalysts with the improved performance and durability for ORR reaction.展开更多
基金financially supported by the National Natural Science Foundation of China (21771084, 21771077, 21621001)the Foundation of Science and Technology Development of Jilin Province,China (20200801004GH)+1 种基金the 111 Project (B17020)financial support by the program for JLU Science and Technology Innovative Research Team (JLUSTIRT)。
文摘The designing of reasonable nanocomposite materials and proper introduction of defect engineering are of great significance for the improvement of the poor electronic conductivity and slow reaction kinetics of manganese-based compounds. Herein, we report manganese-deficient Mn_(3)O_(4) nanoparticles which grow in-situ on highly conductive carbon nanotubes(CNTs)(denoted as DMOC) as an advanced cathode material for aqueous rechargeable zinc-ion batteries(RAZIBs). According to experimental and calculation results, the DMOC cathode integrates the advantages of enriched Mn defects and small particle size. These features not only enhance electronic conductivity but also create more active site and contribute to fast reaction kinetics. Moreover, the structure of DMOC is maintained during the charging and discharging process, thus benefiting for excellent cycle stability. As a result, the DMOC electrode delivers a high specific capacity of 420.6 m A h g^(-1) at 0.1 A g^(-1) and an excellent cycle life of 2800 cycles at 2.0 A g^(-1) with a high-capacity retention of 84.1%. In addition, the soft-packaged battery assembled with DMOC cathode exhibits long cycle life and high energy density of 146.3 Wh kg^(-1) at 1.0 A g^(-1) . The results are beneficial for the development of Zn/Mn_(3)O_(4) battery for practical energy storage.
基金We thank the following funding agencies for supporting this work:the National Natural Science Foundation of China(grant no.21968020 and 22068026).
文摘A fundamental question in the oxygen reduction reaction(ORR)is how to rationally control the electrocatalytic selectivity for opening a four-electron reaction pathway.However,it still lacks direct experimental evidence to understand the reaction mechanism.This work unravels that Ag nanoparticles and carbonizing halloysite nanotubes(CHNTs)can trigger the construction of oxygen defects in the MnO_(2),which contribute to the generation of active sites.The Ag/MnO_(2)-CHNTs delivers a superior activity toward ORR with high onset potential,half-wave potential,diffusion-limited current density,long-term durability and methanol tolerance.More importantly,combined with density functional theory calculations,triggering manganese dioxide defects upon the introduction of Ag nanoparticles and CHNTs can alter the electrocatalytic pathway from a two-electron to a direct four-electron direction for ORR,which is the nature of enhanced ORR activity.Based on the analysis of the results,this finding points out a very effective approach for exploring catalysts with the improved performance and durability for ORR reaction.
