Details

Autor(en) / Beteiligte

• Lin, Ruoqian
• Hu, Enyuan
• Liu, Mingjie
• Wang, Yi
• Cheng, Hao
• Wu, Jinpeng
• Zheng, Jin-Cheng
• Wu, Qin
• Bak, Seongmin
• Tong, Xiao
• Zhang, Rui
• Yang, Wanli
• Persson, Kristin A.
• Yu, Xiqian
• Yang, Xiao-Qing
• Xin, Huolin L.

Titel

Anomalous metal segregation in lithium-rich material provides design rules for stable cathode in lithium-ion battery

Ist Teil von

• Nature communications, 2019-04, Vol.10 (1), p.1650-1650, Article 1650

Ort / Verlag

London: Nature Publishing Group UK

Erscheinungsjahr

2019

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Despite the importance of studying the instability of delithiated cathode materials, it remains difficult to underpin the degradation mechanism of lithium-rich cathode materials due to the complication of combined chemical and structural evolutions. Herein, we use state-of-the-art electron microscopy tools, in conjunction with synchrotron X-ray techniques and first-principle calculations to study a 4 d -element-containing compound, Li 2 Ru 0.5 Mn 0.5 O 3 . We find surprisingly, after cycling, ruthenium segregates out as metallic nanoclusters on the reconstructed surface. Our calculations show that the unexpected ruthenium metal segregation is due to its thermodynamic insolubility in the oxygen deprived surface. This insolubility can disrupt the reconstructed surface, which explains the formation of a porous structure in this material. This work reveals the importance of studying the thermodynamic stability of the reconstructed film on the cathode materials and offers a theoretical guidance for choosing manganese substituting elements in lithium-rich as well as stoichiometric layer-layer compounds for stabilizing the cathode surface. The authors show that after cycling the model cathode material Li 2 Ru 0.5 Mn 0.5 O 3 undergoes ruthenium segregation and even exsolution at the reconstructed oxide surface, which triggers a progressive degradation process. The insights enable new dimensions in choosing dopants for stabilized cathode surface.