Molecular layer deposited mechanically and chemically robust niobicone interface empowering silicon nanowire anodes with competent cyclabilities.

[Display omitted] • A Nb-based hybrid coating for Si anodes was synthesized by MLD and annealing. • The coating provides enhanced tolerance of stress and resistance to side reactions. • A thin, stable LiF-rich SEI layer is established on the Si anode. • Fast Li+ transport kinetics and low stress distribution in the SEI is confirmed. • The Si anode exhibits advantageous rate capability and capacity retention. Silicon material anodes are attractive for a range of high energy density lithium-ion battery applications, but their huge volume expansion, interfacial side reactions, and fast capacity decay are limitations. Herein, molecular layer deposition (MLD) is used to deposit a Nb-based inorganic-organic coating onto casted silicon nanowire (Si NW) electrodes, forming an artificial solid-electrolyte interphase (SEI). Post annealing of the coated composite (Si NW@NbHQ-500) drives a general cross-linking reaction within (-Nb-O-benzene-O-) n units, achieving enhanced mechanical and chemical robustness of the interface. The coating material and its reduced products (Nb4+ species) appear to be involved in a thin and LiF-rich SEI framework, accelerating interfacial Li+ diffusion. With mechanical strain dissipation and natural SEI erosion suppression, the anode exhibits an advantageous rate capability of 940 mAh/g at 4 A/g, a high reversible areal capacity of 4.0 mAh cm−2, an impressive capacity retention with a capacity decay of only ≈0.06 % per cycle over 800 cycles at 1 A/g, as well as a stable full cell electrochemical cycling performance when integrated with a LiFePO 4 cathode. Additionally, SEI modulus test verifies that the Si NW@NbHQ-500 anode undergoes gentle reversible interfacial evolution during cycling with a slight average modulus rise (≈10.3 to 37.9 GPa) from surface to bulk. This work demonstrates the great potential of Nb-based inorganic-organic hybrid nano coatings for mechanical and electrochemical stabilization of silicon anodes. [ABSTRACT FROM AUTHOR]