Scalable fabrication of turbostratic graphene with high density and high ion conductivity for compact capacitive energy storage

Abstract

Massively fabricating graphene with high density and high ion conductivity is critical but challenging for large-scale compact capacitive energy storage with high energy and power densities. Here, we demonstrate an efficient, kilogram-scale method for fabricating dense, turbostratic graphene by turbulent flow and isotropic capillary compression at violent boiling temperature, successfully resolving the trade-off between high density and high ion conductivity, as well as scale producing. Turbostratic graphene exhibits 5.4× enhanced ion conductivity, high density of up to 1.12 g cm⁻³, and volumetric capacitance of 234 F cm⁻³. Stack cells deliver an energy density of 83.2 Wh L⁻¹ and power density of 14 kW L⁻¹, a milestone in capacitive energy storage. Moreover, orientation and porosity of turbostratic graphene can be tuned by precursors, demonstrating flexibility and viability for diverse applications. Furthermore, all-solid-state pouch cells are fabricated using ionic gel electrolyte, exhibiting multiple optional outputs and being leakage free at bending and folding states.