Meaning
Region of carbon material where graphene layers are stacked parallel to one another but exhibit random rotational and translational displacement. A turbostratic domain provides numerous insertion sites that increase the specific capacity of non-graphitizable hard carbon anodes. This structure is common in carbons processed at lower temperatures.
Lattice Disorganization
Misalignment of the graphene sheets creates a highly disordered structure that prevents the formation of a crystalline graphite lattice. This turbostratic domain structure is characterized by a larger interlayer spacing compared to pure graphite. The increased spacing allows for faster lithium or sodium ion diffusion.
Storage Mechanism
Ions are stored not only between the graphene layers but also in the nanopores and defect sites created by the disordered structure. The presence of a turbostratic domain enables the anode to achieve higher capacities than conventional materials. This mechanism is particularly effective for sodium-ion batteries where the larger ion size requires more open structures.
Material Limitation
Disordered carbons often suffer from a lower initial coulombic efficiency due to the high surface area and numerous defect sites. In materials with a large turbostratic domain fraction, the formation of the solid electrolyte interphase consumes a significant portion of the initial lithium or sodium. This consumption reduces the usable energy density of the finished cell, which requires manufacturers to apply pre-lithiation techniques to compensate for the initial loss.
