摘要
Rechargeable Li-O2 batteries (LOBs) have been receiving intensive attention because of their ultra-high theoretical energy densityclose to the gasoline. Herein, Ag modified urchin-like α-MnO2 (Ag-MnO2) material with hierarchical porous structure is obtained bya facile one-step hydrothermal method. Ag-MnO2 possesses thick nanowires and presents hierarchical porous structure of mesoporesand macropores. The unique structure can expose more active sites, and provide continuous pathways for O2 and discharge productsas well. The doping of Ag leads to the change of electronic distribution in α-MnO2 (i.e., more oxygen vacancies), which playimportant roles in improving their intrinsic catalytic activity and conductivity. As a result, LOBs with Ag-MnO2 catalysts exhibit loweroverpotential, higher discharge specific capacity and much better cycle stability compared to pure a-MnO2. LOBs with Ag-MnO2catalysts exhibit a superior discharge specific capacity of 13,131 mA·h·g^-1 at a current density of 200 mA·h·g^-1, a good cycle stabilityof 500 cycles at the capacity of 500 mA·h·g^-1. When current density is increased to 400 mA·h·g^-1, LOBs still retain a long lifespan of170 cycles at a limited capacity of 1,000 mA·h·g^-1.
基金
This work was financially supported by High-level Talents'Discipline Construction Fund of Shandong University(No.31370089963078)
Shandong Provincial Science and Technology Major Project(Nos.2016GGX104001,2017CXGC1010,and 2018JMRH0211)
the Fundamental Research Funds of Shandong University(Nos.2016JC005,2017JC042 and 2017JC010)
the Natural Science Foundation of Shandong Province(No.ZR2017MEM002)
School Research Startup Expenses of Harbin Institute of Technology(Shenzhen)(No.DD29100027).
