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7073155 
Journal Article 
Ag doped urchin-like alpha-MnO2 toward efficient and bifunctional electrocatalysts for Li-O-2 batteries 
Dai, L; Ci, L; Sun, Q; Chen, L; Guo, H; Nie, X; Cheng, Jun; Guo, J; Li, J; Lou, Jun; , 
2020 
1 
Nano Research
ISSN: 1998-0124 
TSINGHUA UNIV PRESS 
BEIJING 
13 
9 
2356-2364 
WOS:000543301300007 
Rechargeable Li-O(2)batteries (LOBs) have been receiving intensive attention because of their ultra-high theoretical energy density close to the gasoline. Herein, Ag modified urchin-like alpha-MnO2(Ag-MnO2) material with hierarchical porous structure is obtained by a facile one-step hydrothermal method. Ag-MnO(2)possesses thick nanowires and presents hierarchical porous structure of mesopores and macropores. The unique structure can expose more active sites, and provide continuous pathways for O(2)and discharge products as well. The doping of Ag leads to the change of electronic distribution in a-MnO2(i.e., more oxygen vacancies), which play important roles in improving their intrinsic catalytic activity and conductivity. As a result, LOBs with Ag-MnO(2)catalysts exhibit lower overpotential, higher discharge specific capacity and much better cycle stability compared to pure alpha-MnO2. LOBs with Ag-MnO(2)catalysts exhibit a superior discharge specific capacity of 13,131 mAhg(-1)at a current density of 200 mAg(-1), a good cycle stability of 500 cycles at the capacity of 500 mAhg(-1). When current density is increased to 400 mAg(-1), LOBs still retain a long lifespan of 170 cycles at a limited capacity of 1,000 mAhg(-1). 
Li-O-2 batteries; Ag doped urchin-like MnO2; electronic structure; cycling stability