Direct Evidence of Reversible SnO2-Li Reactions in Carbon Nanospaces.

We present herein that carbon nanospaces are the key reaction space to improve the reversibility of the reaction of SnO2 with Li-ions for lithium-ion batteries, demonstrated by both ex situ and in situ observations using high-resolution scanning transmission electron microscopy with electron energy loss spectroscopy. Conversion-type electrode materials, such as SnO2, undergo large volume changes and phase separation during the charge-discharge process, which lead to degradation in the battery performance. By confining the SnO2-Li reaction within carbon nanopores, the battery performance is improved. However, the exact phase changes of SnO2 in the nanospaces are unclear. By directly observing the electrodes during the charge-discharge process, the carbon walls are capable of preventing the expansion of SnO2 particles and minimizing the conversion-induced phase separation of Sn and Li2O on the sub-nanometer scale. Thus, nanoconfinement structures can effectively improve the reversibility performance of conversion-type electrode materials.

Citation

Hiroo Notohara, Koki Urita, Isamu Moriguchi. Direct Evidence of Reversible SnO2-Li Reactions in Carbon Nanospaces. ACS applied materials & interfaces. 2023 Jun 28;15(25):30600-30605

PMID: 37314754

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