Electrochemical Unzipping of Carbon Nanotubes in a Molten Salt

The architecture of graphene stacks has a profound effect on their performance in a broad range of applications, including energy storage or catalysis. Despite its high demand, the identification of a material synthesis/processing method that combines structure tunability with high product quality and quantity remains challenging. Here, this long-standing challenge is addressed through the electrochemical unzipping of carbon nanotubes (CNTs) in a molten salt. Contrary to the established chemical oxidation approach for CNT unzipping, the proposed electrochemical process retains an oxygen-free surface and eradicates graphene's structural defects. Moreover, the temperature of the melt determines the architecture of restacked graphene sheets, which transition from few-layered turbostratic to multilayered Bernal-type stacking. While this tunable graphitic structure is herein correlated with its Li-ion battery fast-charging performance, the implications of electrochemical unzipping of CNTs in molten CaCl₂-NaCl are far-reaching, opening up avenues for numerous applications that rely on graphene-like and graphitic structures.