Anomalous Enhancement of Li‐O2 Battery Performance with Li2O2 Films Assisted by NiFeOx Nanofiber Catalysts: Insights into Morphology Control. (27th September 2016)

• Record Type: Journal Article
• Authors: Huang, Jiaqiang; Zhang, Biao; Bai, Zhaowen; Guo, Ruiqiang; Xu, Zheng‐Long; Sadighi, Zoya; Qin, Lei; Zhang, Tong‐Yi; Chen, Guohua; Huang, Baoling; Kim, Jang‐Kyo
• Is Part Of: Advanced functional materials. Volume 26:Number 45(2016)
• Page Start: 8290
• Page End: 8299
• Publication Date: 2016-09-27
• Subjects: heterogeneous nucleation -- Li2O2 films -- lithium‐oxygen batteries -- morphology control -- oxygen‐rich Li2O2; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201603178
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract : It is generally understood that particle‐shaped Li2 O2 is preferred in Li‐O2 batteries (LOBs) because the dominance of Li2 O2 films may lead to poor electrochemical performance. The influence of Li2 O2 morphology and its nucleation mechanism are probed by experiments along with the first‐principle calculations. It is revealed that the LOBs with Li2 O2 films deliver unexpectedly improved capacities, longer cycles, and significantly reduced overpotentials assisted by NiFeO x nanofiber catalysts. The energetically favored Li 2a vacancies under LiO2 ‐rich conditions, small crystallites, and large contact areas with the electrode/electrolyte explain the anomalous performance enhancement. Li2 O2 films are formed by a heterogeneous nucleation mechanism and the voltage applied, electrolyte, electrode surface, and use of catalysts are identified as the parameters controlling the mechanisms. The mapped correlations among these parameters shed light on the control of Li2 O2 morphology for developing high‐performance LOBs. Abstract : The film‐shaped discharge product, Li2 O2, has long been considered detrimental for Li‐O2 batteries because it may lead to premature cell death. Contrary to this, it is revealed that the Li2 O2 films ameliorate the battery's electrochemical performance when assisted by NiFeO x catalysts. The presence of Li vacancies, small size crystallites, and large contact areas with the electrode/electrolyte provides solid evidence of this finding.