Interest in all-solid-state batteries (ASSBs), particularly the anode-less type, has grown alongside the expansion of the electric vehicle (EV) market, because they offer advantages in terms of their energy density and manufacturing cost. However, in most anode-less ASSBs, the anode is covered by a protective layer to ensure stable lithium (Li) deposition, thus requiring high temperatures to ensure adequate Li ion diffusion kinetics through the protective layer. This study proposes a dual-seed protective layer consisting of silver (Ag) and zinc oxide (ZnO) nanoparticles for sulfide-based anode-less ASSBs. This dual-seed-based protective layer not only facilitates Li diffusion via multiple lithiation pathways over a wide range of potentials, but also enhances the mechanical stability of the anode interface through the in situ formation of a Ag-Zn alloy with high ductility. The capacity retention during full-cell evaluation is 80.8% for 100 cycles when cycled at 1 mA cm^-2 with 3 mAh cm^-2 at room temperature. The dual-seed approach provides useful insights into the design of multi-seed concepts in which, from a mechanochemical perspective, various lithiophilic materials synergistically impact upon the anode-less interface.

Abstract Silicon anodes with high energy density are prone to mechanical deformation during cycling, including fracture, pulverization, and delamination from conductive materials, due to their large volume expansion and contraction. Although significant attention is paid to outer interface engineering such as surface coating and electrolyte design in order to maintain a steady solid electrolyte interphase (SEI), there are currently few strategies in place for stabilizing the inner interface between Si and conductive carbon host materials. In this work, it is reported that an interfacial SiC chemical bonding enhances the interaction between Si and carbon, which in turn suppresses nano‐sized void evolution and ensues Si delamination. Through the open‐edge structure of carbon nanotube (OCNT), it is demonstrated that graphitic edge planes enable to evoke of interfacial SiC specifically at the junction without overgrowth toward the bulk. As a result, an Si‐graphite composite consisting of interfacial SiC exhibits a sF cycling life (79.5% for 300 cycles at 3C charging), as well as lower overpotential under high current density up to 5C compared to paired LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM) cathode in pouch full‐cell tests. This study highlights the significance of inner interface engineering for developing high‐energy density Si‐based anodes toward fast charging and long‐term stability.