Inorganic Gel-Derived Metallic Frameworks Enabling High-Performance Silicon Anodes.

ABSTRACT

Metallic matrix materials have emerged as an ideal platform to hybridize with next-generation electrode materials such as silicon for practical applications in Li-ion batteries. However, these metallic species commonly exist in the form of isolated particles, failing to provide enough free space for silicon volume changes as well as continuous charge transport pathways. Herein, three-dimensional (3D) metallic frameworks with interconnected pore channels and conductive skeletons, have been synthesized from inorganic gel precursors as buffering/conducting matrices to boost lithium storage performance of silicon anodes. As a proof-of-concept demonstration, commercial Si particles are in situ immobilized within the Sn-Ni alloy framework via a facile gel-reduction route, and the rearrangement of Si particles during cycling increases the dispersity of Si in the Sn-Ni framework as well as their synergic effects toward lithium storage. The Si@Sn-Ni all-metallic framework manifests high structural integrity, 3D Li+/e- mixed conduction pathway, and synergic effects of interfacial bonding and concurrent reaction dynamics between active Si and Sn, enabling long-term cycle life (1205 mA h g-1 after 100 cycles at 0.5 A g-1) and superior rate capability (653 mA h g-1 at 10 A g-1).