Graphite Cathode for EV Batteries
The graphite cathode is a critical component in electric vehicle (EV) batteries because it hosts Li-ions, which store energy in the battery when they are charged. The demand for EVs is escalating, which requires a dependable and plentiful supply of specialized graphite.
Graphite has many desirable properties, including its low cost, chemical inertness and ability to conduct electricity. It is also simple to shape into a rod and hard-wearing, which makes it an ideal electrode material for electrolysis applications.
In situ X-ray diffraction patterns and Raman spectra of graphite used as the cathode in an aluminum ion battery were recorded through a charge-discharge cycle showing chloroaluminate anion intercalation/de-intercalation into graphite. Ex situ X-ray diffractions showed the formation of two distinct plateaus at the charging voltage of 1.99 V and 2.37 V, with the E2g2(i) peak becoming stronger along with a smaller peak in the E2g2(b) mode.
Raman spectra of the NG cathode at the charging voltage of 1.99, 2.37, 2.42 and 2.45 V and discharging voltage of 2.3, 2.24, 1.8 and 0.5 V were recorded during the charge-discharge process for hundreds of cycles. The NG electrode exhibited no apparent D band, which indicates that the graphite is maintaining its structure throughout this long-term cycling of chloroaluminate anion intercalation/de-intercalation.
Despite the large variation in charge capacity, the GLGs with smaller interlayer distance exhibited higher coulombic efficiency. This was likely because the oxygen-containing groups did not activate the oxidation of the electrolyte solution and irreversibly trap the anions.
