Encapsulating Tin Nanoflowers into Microcapsules for High‐Rate‐Performance Secondary Battery Anodes through In Situ Polymerizing Oil‐in‐Water Interface

Abstract

Large volume expansion and structural breaking have been severe issues for emerging high‐performance secondary battery anodes. Herein, a novel microcapsule anode filled with tin (Sn) nanoflowers is presented, which is prepared through in situ interface polymerization of an oil‐in‐water emulsion system. The carbon shell of the microcapsules reduces the pulverization of the encapsulated Sn, and the voids inside the capsules provide efficient spaces for the volume change of Sn during lithiation–delithiation. The Sn‐filled microcapsules exhibit a high rate performance with a capacity decay rate as low as 0.38%, even after three rounds of repeated tests, and a stable capacity of 800 mAh g−1 after 200 cycles at 380 mA g−1. In addition, the electron transfer kinetics and Li‐ion diffusion are investigated, which indicate that the microcapsule system enables a good environment for both electron and ion transfer.