Nanoarchitectured in situ pre-lithiated carbon anodes for high-power and long-life Li-ion capacitors

Abstract

Lithium-ion capacitors (LICs) combine high energy and power densities but often suffer from poor cycle stability (<10 000 cycles) due to uncontrolled Li⁺ ion losses during solid electrolyte interphase (SEI) layer formation and irreversible side reactions. From an industrial standpoint, achieving >20 000 cycles necessitates an adequate pre-lithiation strategy that efficiently replenishes ions to offset such losses. This work proposes a scalable pre-lithiation approach by adding a thin piece of lithium metal foil (46 μm) in direct contact with the anode while assembling LICs. The electrochemical potential difference between the Li foil and the carbon-coated porous current collector anode facilitates the lithiation process and promotes in situ pre-lithiation (ISP). After a 10 h pre-lithiation time, the resultant LiCx and SEI layer were verified by ex situ characterization studies. The optimized LIC demonstrated a best-in-class specific energy of 204 Wh kg⁻¹ and a specific power of 5.5 kW kg⁻¹. The device achieved a remarkable capacity retention of 87% after 40 000 full charge–discharge cycles, equivalent to 631 h. This structurally engineered strategy underscores the critical role of pre-lithiation in advancing next-generation, high-performance energy storage solutions.