Meaning
Carbonaceous binding precursors provide high purity carbon coatings that protect and stabilize the anode materials in lithium ion batteries. The utilization of coal tar pitch produces a dense, graphitizable carbon layer when heat treated under inert atmospheres. This protective coating reduces the surface area of active anode materials, which limits the initial capacity loss during the first charge cycles.
Decreasing the surface reactivity also minimizes the consumption of lithium during the formation of the solid electrolyte interphase.
Carbon Precursor
Sourcing this material involves the distillation of crude coal tar to yield a thermoplastic residue rich in aromatic compounds. The viscous liquid fills the microscopic pores of synthetic graphite particles, ensuring a uniform distribution of the precursor. This raw residue is chosen for its high carbon yield and compatible softening point.
Anode Processing
Mixing the carbonaceous material with graphite powder occurs at elevated temperatures before the shape is finalized. Applying this layer helps to shield the active graphite from direct contact with the liquid electrolyte. This coating process decreases the rate of solvent co intercalation, which extends the operational life of the anode.
Thermal Treatment
Pyrolysis at temperatures exceeding one thousand degrees Celsius converts the organic layer into a highly conductive carbon matrix. This high temperature step removes volatile elements, leaving behind a carbon layer that conducts electricity efficiently. The final treated powder displays superior performance under high discharge rates.
