Interfacial Chemistry and Lithiophilicity Design for High Energy Hybrid Li‐Ion/Metal Batteries in a Wide Temperature Range

Abstract Hybrid Li‐ion/metal batteries can optimize energy density and lifespan. However, hybrid batteries face key obstacles like poor Li reversibility and dendrite growth. Herein, carbon nanofibers encapsulated by graphitized layers decorated with uniformly distributed Ag nanoparticles (G‐CF‐Ag) are designed, and interfacial chemistry is regulated to enhance the performance of hybrid batteries. The C sp2 carbon structure in graphitized layers effectively reduces side reactions with electrolytes, and Ag nanoparticles improve lithiophilicity and induce uniform Li plating/stripping. A weakly solvated electrolyte of 1 m LiFSI‐THF‐0.5wt.%LiNO 3 induces interfacial chemistry to achieve rapid transport of Li‐ions under fast charging conditions and low temperatures. Consequently, with a high‐capacity Li deposition of 500 mA h g −1 (≈1.25 mA h cm −2 ), the G‐CF‐Ag||Li delivers an ultra‐high plateau capacity of 716 mA h g −1 at voltages below 0.1V at 0.2 C, and maintains an average CE of 99.1% over 150 cycles at 2 C fast charging. Notably, the cell continues to operate stably even in a wide temperature range from 50°C to ‐20°C. Furthermore, at an ultra‐low N/P ratio of 0.3, the G‐CF‐Ag||NCM811 provides a high energy density of 587.5 W h kg −1 at 0.2 C. At the same N/P ratio, the G‐CF‐Ag||LFP maintains stable cycling in a wide temperature range from 50°C to ‐20°C.