In light of the escalating importance of batteries for broad applications in modern societies, it is crucial to establish a sustainable strategy that pinpoints and addresses the scientific challenges in battery manufacturing. For academic researchers, manufacturing seems a little far from their daily research, as they are not familiar with the manufacturing process which is usually taken care of by industry. It is not clear what kind of roles researchers can play in supporting battery manufacturing. Meanwhile, for industry, most of the published research is valuable in deepening scientific understanding, but there is still uncertainty whether those new materials or ideas are suitable for large-scale production, (1) because the first criterion to assess the feasibility of any new material, component, or battery technology is the cost, which includes both materials and processing.

The cost of Li-ion batteries (LIBs) has dropped significantly from a few thousand dollars per kWh in the 1990s to around $100/kWh today. (2) However, to further accelerate electric vehicle (EV) market penetration and enable large-scale deployment of grid energy storage, the cost must be reduced below $100/kWh. Achieving this requires cost-efficient materials and processing technologies along with increased cell-level energy density, (3) because the cost of a battery is defined as $$/kWh. In addition to the cell-level energy from each building block of the pack, battery lifetime─that is, the total deliverable energy during the lifespan of the battery─also plays a key role in determining the cost in the long term, which needs more fundamental understanding about stabilizing the structures of cathodes and their interfaces, which is not the focus of this Review. CO2 emission from battery manufacturing has been covered by quite a few review papers (4−8) and thus will not be discussed herein.

Fundamental research related to battery manufacturing needs to be cost oriented. For conventional LIBs, graphite production is quite mature. To further reduce the cost of graphite production, natural graphite is of great importance, but its electrochemical performance still needs further improvement without introducing an additional cost. The manufacturing of high-performance graphite also relies on equipment such as specialized furnaces to precisely tune the temperatures and heating environments to control the electrochemical properties of carbon. Hard carbon is also proposed for LIBs and, so far, is the best anode material for Na-ion batteries. Synthesis of hard carbon from sustainable resources is one of the promising directions from a manufacturing cost and scalability point of view.

For the conventional LiNi0.6Mn0.2Co0.2O2 (NMC622) cathode, the manufacturing costs fluctuate with raw material prices, including lithium salts and transition metal sulfates. Additionally, various synthesis approaches also impact the production cost of NMC materials... (9)

Figure 1. A simplified process diagram for lithium carbonate production with lithium brine extraction and hard rock mining.

Figure 2. Process flow for LiPF6 production.

Figure 3. Flowchart illustrating the manufacturing process for graphite anode materials.

Figure 4. (a) Illustration of molten salt electrolysis to produce Li metal ingots.

Figure 5. Manufacturing processes to convert different copper ores into pure copper.