In situ TEM study of structure evolution of porous hollow carbon sphere/sulfur cathodes

Great progresses on improving capability and stability of lithium-sulfur batteries (LSBs) by developing novel electrodes and electrolytes have been achieved. However, the study on the electrochemical conversion of sulfur with their volume expansion is limited, but provides another promising approach to further promote the practical application of LSBs. Herein, we successfully synthesize porous hollow carbon spheres as the host for sulfur in LSBs. In situ transmission electron microscopy (TEM) is applied to track the real-time morphological and structural evolutions of the porous hollow carbon sphere/sulfur composite when lithiation occurs. A small volume expansion of 39.4% from its original state is observed, benefiting from the highly porous structure of carbon. As a result, the composite electrode achieves a high residual capacity of 712 mAh g-1 after 200 cycles.