Formation protocol design in lithium-ion batteries: pathways toward manufacturable fast formation

Lithium-ion battery (LIB) formation is a critical manufacturing step that determines the initial electrochemical and interfacial state of the cell, strongly affecting irreversible lithium loss, impedance growth, gas evolution, cycle life and production cost. This review presents a classification-centered and mechanism-linked framework for formation protocol design, with particular emphasis on how current-profile architecture enables manufacturable fast formation. The review examines the mechanistic effects of current-program design, comparing single-current, CC-only versus CC-CV, multistage, pulse or intermittent, and plating-aware fast protocols in relation to SEI/CEI development, lithium plating, resistance evolution, and chemistry-dependent behavior. The key finding from the literature is that fast formation is not inherently detrimental. The success depends on the coordinated control of current, voltage window, temperature, pressure and endpoint conditions.The review further identifies practical requirements for industrial fast formation, including chemistry-specific optimization, in-line diagnostics, mechanistic modeling, data-driven screening and standardized techno-economic evaluation. Overall, this review highlights protocol design as a manufacturable pathway to reduce formation time while preserving interphase stability, quality control and long-term cell reliability.