Electrochemical Unzipping of Carbon Nanotubes in a Molten Salt

ABSTRACT 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 CaCl ₂ ‐NaCl are far‐reaching, opening up avenues for numerous applications that rely on graphene‐like and graphitic structures.