Interfacial engineering between hard carbon and solid electrolytes using perylene-based carbon layers for all-solid-state batteries

The development of negative electrode materials that combine high capacity, high rate capability, and excellent durability remains a critical challenge for sulfide-based all-solid-state lithium-ion batteries (ASSLIBs). Herein, we demonstrate that the surface modification of hard carbon (HC) with a partially carbonized 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) coating not only enables its application as a promising negative electrode material but also offers critical insights into the role of interfacial contact. A non-uniform coating layer with a thickness of 2–150 nm was introduced while preserving the pore structure of the HC. The surface-modified HC delivered a reversible capacity of approximately 600 mAh g −1 with an initial coulombic efficiency of ~85%, representing an increase of 100 mAh g −1 and 10% over the uncoated HC, respectively. The increased reversible capacity was ascribed to an improved Li-ion transport resulting from the superior interfacial adhesion between the HC and solid electrolyte. Furthermore, the surface-modified HC exhibited enhanced charging rate capability and capacity retention, highlighting its potential as a high-performance negative electrode material for ASSLIBs. These findings underscore the decisive role of interfacial contact in determining electrochemical performance. This study provides a design principle for tailoring HC surfaces and opens new possibilities for developing high-performance negative electrode materials for ASSLIBs.