Robust and Fast‐Ion Conducting Interphase Empowering SiOx Anode Toward High Energy Lithium–Ion Batteries

Abstract Silicon suboxides (SiO x ) materials are highly desirable as anode for high energy Li‐ion batteries due to their much higher specific capacity than conventional graphite anode. However, the low initial Coulombic efficiency (ICE) and inadequate capacity retention of SiO x anode arising from its immense volume variation during repeated lithiation/delithiation process greatly hinder its practical applications. To address these drawbacks of SiO x , by a simple calcination method, a robust and fast‐ion conducting interphase enriched of LiF, Li 2 C 2 O 4 , LiBO 2 , and Li 2 B 4 O 7 is rationally pre‐constructed With the assistance of this pre‐constructed artificial protective layer, the formed solid‐electrolyte interphase (SEI) layer possesses high Young's modulus and fast Li + conducting, and thus can accommodate the plastic deformation of SiO x anode, alleviate the parasitic reactions, and maintain the electrode integrity upon cycling. Thus, the modified SiO x (M‐SiO x ) anode exhibits higher ICE, better capacity retention and superior rate capability. More encouragingly, full cells pairing the M‐SiO x anode with LiNi 0.8 Mn 0.1 Co 0.1 O 2 cathode show a high capacity retention of 80.6% for 200 cycles. This paper reveals the importance of pre‐constructing an artificial SEI layer and regulating interfacial chemistry in improving the performance of SiO x ‐based anodes, which is a milestone work for boosting the large scale application of SiO x ‐based anodes.