PNNL

Abstract

Alloy-based anodes of nanostructure have the privilege of alleviating the challenges of the large volume expansion and improving the cycling stability and rate performance for high energy lithium- and sodium-ion batteries (LIBs and SIBs). Yet, it faces the dilemma of worsening the parasitic reactions at the electrode-electrolyte interface and low pack density for practical electrode fabrication. Here, pomegranate Sb@C yolk-shell microspheres were developed as a high-performance anode for LIBs and SIBs with controlled interfacial properties and enhanced packing density. Although the same yolk-shell nanostructure (primary particle size, porosity) and three-dimensional architecture alleviated the volume change induced stress and swelling in both batteries, the SIB shows 99% capacity retention over 200 cycles, much better than the 78% capacity retention of LIBs. The comparative electrochemical study and X-ray photoelectron spectroscopy characterization revealed that the different SEI, besides the distinct phase transition mechanism, played a critical role in the divergent cycling performance.