Pyrochlore phase Ce2Sn2O7via an atom-confining strategy for reversible lithium storage

TLDR: In this article, a pyrochlore phase anode material, Ce2Sn2O7, was proposed, which shows atomic Sn confined in a conductive 3D percolating Ce-O framework.

Abstract: In the search of high-performance anode materials for next-generation Li-ion batteries, more efforts are needed on new structural prototypes. Motivated by the negative thermal expansion effect in a loosely packed crystal structure type, we are intrigued by the possibility of exploiting new anode materials in a suitable phase structure with much-reduced intrinsic volume strain. Herein, we report a new pyrochlore phase anode material, Ce2Sn2O7, which shows atomic Sn confined in a conductive 3D percolating Ce–O framework. Based on the concept of structural openness, pyrochlore Ce2Sn2O7 possesses open structures to tolerate the volume change. Notably, the Ce–O network is quite robust against the charge/discharge process, which accounts for the high structural stability observed in the experiment. Ultimately, Ce2Sn2O7 electrodes achieve a capacity as high as 631.1 mA h g−1 and excellent cycling stability. This atom-confining strategy of atomic Sn in the conductive 3D percolating Ce–O framework might be exploited as a general strategy for reducing cycling strain in ion-storage materials.