Robust chemo-mechanical stability of additives-free SiO2 anode realized by honeycomb nanolattice for high performance Li-ion batteries

Abstract

Silicon-based anodes including Si, SiOx and SiO2 could deliver ultra-large capacities, but degrade fast owing to huge volume change and low conductivity. Generally, large amounts of elastic binder and conductive additives were composited with nanosized silicon-based materials to yield reasonable cycling stability, which nevertheless not only decrease specific capacity but also induce inhomogeneous lithiation/delithiation as well as uneven stress variations. Artificial nanolattice has exhibited superior mechanical properties which could be ideal structure for silicon-based anodes, but yet faces challenges in integration of chemical reactivity, conductivity and mechanical stability. Herein, we fabricate artificial SiO2 honeycomb nanolattice consisting of numerous nanoscale SiO2 cells interconnected by through-holes, and conformal coating of highly graphitic carbon on the nanolattice is achieved through in situ catalytic graphitization. Moreover, the nanolattice is firmly bonded on Cu substrate through atomic interdiffusion irrespective of surface roughness. This unique structure allows fast charge transportation and homogeneous lithiation/delithiation throughout the micron-meter nanolattice, which results in excellent stability and large reversible capacity over 500 cycles at 1 A/g. The results highlight design and constructing artificial nanolattice can be an effective way to prevent chemo-mechanical degradation of silicon-based anode materials.