Self-sacrificing assisted porous engineering: A general pathway for fast and stable lithium storage of yolk-shell metal sulfides

Abstract

Structure engineering of yolk-shell design holds the key to prolonging the cycle life of conversion- and alloy-type electrode materials. The limited contacting area between the yolk and shell, however, dramatically constrain the charge transfer paths, resulting in sluggish kinetics. Herein, a general strategy of self-sacrificing assisted porous engineering is presented and implemented towards a series of metal sulfides for fast and stable lithium storage. By virtue of the engineered porous core and uniform shell, the intermediates dissolution and volume expansion are obviously alleviated, while ensuring fast reaction kinetics of metal sulfides. As a representative, the porous-yolk@shell structured FeS exhibits a reversible capacity of 425 mAh/g after 1000 cycles at a current density of 0.5 A/g and a stable capacity of 321 mAh/g even at 10 A/g. This method has been successfully extended to other kind metal sulfides including Co9S8 and Ni3S2, which exhibit stable and fast lithium storage performance.