Mitigating Anolyte-Free Si Anode Failure in All-Solid-State Lithium-Ion Batteries via Roll-Transfer Printing Prelithiation and Soft Metal Conductive Additives

The application of anolyte-free Si anodes containing ≥95 wt % micro-Si material in sulfide-based all-solid-state lithium-ion batteries (ASSLIBs) represents a highly promising route toward achieving high energy density. Nevertheless, their practical implementation is hindered by low initial Coulombic efficiency and poor cycling stability, which originate from the rapid interfacial chemomechanical degradation of Si. To overcome these limitations, we incorporate lithium-active soft metals (e.g., In, Sn, and Al) into anolyte-free Si electrodes and further prelithiate the composite by a solvent-free, scalable roll-transfer printing technique. It is found that the lithiated soft metals function as robust mixed ionic-electronic conductors, serving as a self-adaptive conductive phase that buffers stress and helps preserve interfacial contact during Si volume changes. This effect helps alleviate stress concentration and preserve ionic/electronic percolation pathways during cycling. Accordingly, the optimized anode with 40 wt % In (PLi-6Si4In) delivers stable long-term cycling. When coupled with a high-areal-loading LiNi 0.7 Co 0.2 Mn 0.1 O 2 cathode (26.5 mg cm −2 ), the full cell exhibits 72.7% capacity retention after 700 cycles at 0.5C at room temperature. To meet practical requirements, we also fabricate full cells with ultra-high cathode loading (39.7 mg cm −2 ) and a negative-to-positive electrode capacity ratio (1.32), approaching industrial specifications, which maintain 81.8% capacity retention after 100 cycles. These findings highlight that combining roll-transfer printing prelithiation with lithium-active soft metal buffering effectively addresses the persistent challenge of chemomechanical degradation in Si anodes, advancing the development of all-solid-state batteries toward commercial viability.