Unveiling the Stress‐Buffering Mechanism of Deep Lithiated Ag Nanowires: A Polymer Segmental Motion Strategy toward Ultra‐Robust Li Metal Anodes

Abstract

AbstractThe severe volume expansion and uncontrolled mechanical stress restrict the high‐areal‐capacity Li storage in the alloy‐type or metallic anodes. Hitherto, most of the mitigation coating strategies are still based on the “trial‐and‐error” attempts, without the quantitative elucidation of the stress‐relaxation mechanism. This article herein constructs a prototypical coating model based on the Si‐O bonding, with the virtual and experimental screening of various structural parameters (for instance, the thickness, elasticity and cross‐linking density), for the deep lithiation of the Ag nanowires (AgNWs) framework. The operando X‐ray diffraction analysis and density functional theory calculations show that γ2(Li10Ag3) exhibits the highest Li affinity to induce the piled‐up deposits till 10 mA h cm–2; while the molecular dynamics simulations depict the optimal stress‐buffering pattern of the segmental motion in polydimethylsiloxane (PDMS) coating layer. As pairing the integrated anode of the AgNWs@PDMS slurries that casted on the AlOx modified polyethylene separator with the NMC‐811 cathode (12.5 mg cm–2), the constructed single‐layer pouch cell can balance the robust cyclability even at the mechanical deformations. This study demonstrates a tentative inverse design strategy to realize the stress‐buffering purpose upon the priori defining of the structural properties.