Hierarchically structured embossed current collectors with multi-primer carbon layers for high-performance catholyte-based solid-state lithium-ion batteries

Abstract

Lithium-ion batteries (LIBs) are widely used as essential energy storage systems in consumer electronics, electric vehicles (EVs), and energy storage systems (ESS) due to their high energy density and long service life. However, conventional LIBs with liquid electrolytes pose significant safety risks, including electrolyte leakage, flammability, and electrochemical instability under high-voltage conditions. To address these challenges, solid polymer electrolytes (SPEs), particularly those based on polyethylene oxide (PEO), have emerged as promising alternatives because of their thermal stability and favorable interfacial compatibility with lithium metal. To enhance ionic conduction and improve interfacial contact between the cathode and the solid electrolyte, catholyte architectures that incorporate solid electrolytes into the cathode have attracted considerable attention. Despite their advantages in ionic transport, these structures often suffer from poor electronic conductivity and interfacial stiffness at the metal current collector, leading to electrode delamination and increased internal resistance. In this study, we introduce an interfacial engineering strategy based on the sequential deposition of graphene and plasma-treated carbon nanotubes (PCNT//G) onto a surface-embossed aluminum (EAl) current collector. This design leverages the combined effects of microstructural embossing for physical adhesion, along with the corrosion resistance, electrical conductivity, and chemical adhesion provided by the carbon layers, thereby improving interfacial stability and charge transport without requiring additional inorganic fillers. The PCNT//G-coated EAl (PCNT//G/EAl) current collector demonstrated excellent electrochemical performance, delivering a specific capacity of 204.4 mA h g-1 at 0.2C and retaining 53.4 mA h g-1 at 2C. These results highlight a scalable and effective strategy for advancing the practical application of catholyte-based all-solid-state LIBs.