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

The 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 AlO_x 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.