High‐Purity Graphitic Carbon for Energy Storage: Sustainable Electrochemical Conversion from Petroleum Coke

The petroleum coke (PC) has been widely used as raw materials for the preparation of electrodes in aluminium electrolysis and lithium‐ion batteries (LIB), during which massive CO(2) gases are produced. To meet global CO(2) reduction, an environmentally friendly route for utilizing PC is highly required. Here, a simple, scalable, catalyst‐free process that can directly convert high‐sulfur PC into graphitic nanomaterials under cathodic polarization in molten CaCl(2)‐LiCl at mild temperatures is proposed. The energy consumption of the proposed process is calculated to be 3 627.08 kWh t(−1), half that of the traditional graphitization process (≈7,825.21 kWh t(−1) graphite). When applied as a negative electrode for LIBs, the as‐converted graphite materials deliver a competitive specific capacity of ≈360 mAh g(−1) (0.2 C) compared with commercial graphite. This approach has great potential to scale up for sustainably converting low‐value PC into high‐quality graphite for energy storage.