Lithium-ion batteries (LIBs) have become one of the main energy storage solutions in modern society. The application fields and market share of LIBs have increased rapidly and continue to show a steady rising trend. The research on LIB materials has scored tremendous achievements. Many innovative materials have been adopted and commercialized by th. Electrochemical Energy StorageIndustrial ChemistryEnergy StorageIndustrial Processing of MaterialLithium-ion batteries (LIBs) have been widely used in portable electronics, electric vehicles, and grid storage due to their high energy density, high power density, and long cycle life. Since Whittingham discovered the intercalation electrodes in the 1970s, Goodenough et al. developed some key cathode materials (layered, spinel, and polyanion) in the 1980s and the 1990s, and Yoshino created the first safe, production-viable LIB with the combination of LiCoO2 as the cathode and carbon/graphite as the anode, much progress in LIBs have been made in terms of cost, energy density, power density, safety, and cycle life (Whittingham, 1976; Mizushima et al., 1980; Thackeray et al., 1983; Padhi et al., 1997). For example, the cost of LIBs has dropped from over $1,000/kWh in the early 2000 to ∼$200/kWh currently. At the same time, the specific energy density of LIBs has been increased from 150 Wh/kg to ∼300 Wh/kg in the past decades. Although beyond LIBs, solid-state batteries (SSBs), sodium-ion batteries, lithium-sulfur batteries, lithium-air batteries, and multivalent batteries have been proposed and developed, LIBs will most likely still dominate the market at least for the next 10 years.Currently, most research studies on LIBs have been focused on diverse active electrode materials and suitable electrolytes for high cutoff voltage applications, especially the nickel-rich and/or cobalt-free cathode materials and Si or Li met. LIB industry has established the manufacturing method for consumer electronic batteries initially and most of the mature technologies have been transferred to current state-of-the-art battery production. Although LIB manufacturers have different cell designs including cylindrical (e.g., Panasonic designed for Tesla), pouch (e.g., LG Chem, A123 Systems, and SK innovation), and prismatic (e.g., Samsung SDI and CATL), the cell manufacturing processes are very similar.Figure 1 introduces the current state-of-the-art battery manufacturing process, which includes three major parts: electrode preparation, cell assembly, and battery electrochemistry activation. First, the active material (AM), conductive additive, and binder are mixed to form a uniform slurry with the solvent. For the cathode, N-methyl pyrrolidone (NMP) is normally used to dissolve the binder, polyvinylidene fluoride (PVDF), and for the anode, the styrene-butadiene rubber (SBR) binder is dissolved in water with carboxymethyl cellulose (CMC). The slurry is then pumped into a slot die, coated on both sides of the current collector (Al foil for cathode and Cu foil for the anode), and delivered to drying equipment to evaporate the solvent. The common organic solvent (NMP) for cathode slurry is toxic and has strict emission regulations. Thus a solvent recovery process is necessary for the cathode production during drying and the recovered NMP is reused in battery manufacturing with 20%–30% loss (Ahme. It is certain that LIBs will be widely used in electronics, EVs, and grid storage. Both academia and industries are pushing hard to further lower the cost and increase the energy density for LIBs. Compared with the very dynamic research on different materials in the LIB field, the research and development of manufacturing technologies lack impactful progress. From the analysis of different manufacturing steps, it is clearly shown that the steps of formation and aging (32.16%), coating and drying (14.96%), and enclosing (12.45%) are the top three contributors to the manufacturing cost of LIBs; formation and aging (1.5–3 weeks), vacuum drying (12–30 h), and slurry mixing (30 min–5 h) contribute the most in the production time; drying and solvent recovery (46.84%) and dry room (29.37%) contribute the most in energy consumption. Innovations of these steps make great impacts on LIB manufacturing, although other manufacturing steps are also important.Table 2 is the summary of different manufacturing processes with associated methods, significance, and challenges. However, most manufacturing innovations have been reported with very limited adoption by the industry. The most notable case is that Tesla acquired Maxwell and announced to use the dry manufacturing technology in its battery fabrication. We hope that such a perspective can spark the manufacturing innovations that will be applied in th.
