From bulky Si to porous medium entropy alloy: Enabling highly efficient Li storage via the simultaneous reconstruction of microstructure and component

We show here that the Li-storage performance of Si anode can be substantially improved by engineering a multilevel nanoporous SiGeTiZnCuAl medium entropy alloy (NP-MEA). The NP-MEA is directly engineered through a corrosion-driven phase and structure simultaneous reconstruction by partially etching Al and Zn from the multi-element master alloy. The unique multi-elemental interactions can revolutionize the chemical microenvironment, and thus stabilize the structure and impel the transportation of the electrons and ions. The metallic sponge offers multilevel pore channels for electrolyte permeation and ample space for volume change accommodation, abundant accessible active sites for lithiation/delithiation, as well as the rigid skeleton for expediting the electron transportation and stabilizing the structure. Benefiting from the synergy of component and structure, the NP-MEA delivers a high reversible capacity of 646.1 mAh g−1 after 500 cycles at a current density of 2 A g−1.