Lithium-ion batteries (LIBs) are made up of two electrode materials in which Li+ ions are reversibly intercalated back and forth, giving electrical power to an external circuit. The research indicates that LIBs’ commercial success resulted in the incorporation of materials of minimal added value, such as natural graphite.
The mass of graphite accounts for approximately 15-20 percent of the weight of batteries powering electric vehicles, accounting for over 10% of the batteries’ economic value. A priori, recycling, appears to provide apparent environmental benefits, such as increased resource efficiency, decreased carbon emissions, and waste reductions. As a result of battery recycling operations, spent graphite generally contains undesirable metal impurities (Li, Al, Co, Cu, Ni, Fe, and Mn), organic electrolytes, and polymeric binders.
Graphite recycling/regeneration has been accomplished through a variety of techniques, such as hydrometallurgical methods based on acid-base leaching processes (for example, using acids HCl or H2SO4) or a pyrometallurgical process in which graphite is treated at temperatures above 1000 °C to gasify residual metals, metal oxides, and binders, and repair the graphite structure.
The life cycle assessment (LCA) method allows for the quantification of the environmental consequences of recycling operations. LCA may be used to establish the full environmental sustainability of batteries by analyzing the contribution of recycling mechanisms to indicators like global warming, ozone layer depletion potential, ecotoxicity, eutrophication, or acidification that can be estimated.