Native minerals boost the performance of coal-derived hard carbon at low pyrolysis temperatures

Abstract In response to the growing demand for energy-efficient and sustainable industrial processes, this study investigates the use of gagat—a naturally occurring, coal-like material, as a low-cost and scalable precursor for hard carbon (HC) anodes in sodium-, lithium-, and potassium-ion batteries. HC was synthesized using a one-step, low-temperature pyrolysis process, eliminating the need for chemical purification and improving energy efficiency and environmental friendliness. The resulting gagat-derived HC (GHC) exhibits tunable nanoporosity, governed by the pyrolysis temperature, and incorporates electrochemically active mineral phases that enhance performance. The GHC anodes deliver competitive electrochemical performance and high cycling stability across Na- and Li-ion systems. Due to its abundance, simple processing, and residual minerals that enhance the plateau capacity by ∼43% compared to washed material, gagat shows strong potential for next-generation energy storage.