Cell Design and Materials: Li-Ion

High-Voltage Cathodes - Opportunities, Challenges, and R&D Trends The theoretical voltage limit of a cathode material is defined by its active elements' redox potentials. NCM naturally delivers a higher voltage than LFP because Ni, Mn, and Co ions have higher redox potentials than Fe ions [1]. The practical voltage limit can be increased by optimizing particle morphology toward single crystal, tuning element ratios to raise Mn content, and applying doping or coatings to stabilize the crystal structure and minimize side reactions.

The high-voltage battery market is growing rapidly, driven by demand for long-range EVs, advanced AI enabled consumer electronics, and high-capacity energy storage. Higher voltage enables greater capacity and more energy delivery per unit of cathode material. Current high voltage R&D trends focus on high-voltage LCO, single-crystal mid-Ni NCM, and LMR

High-voltage LCO is well suited for high-energy applications, including AI-enabled consumer electronics and drones.

Single-crystal mid-Ni NCM leverages high voltage to compensate for mid-Ni’s lower capacity while improving safety compare to high-Ni NCM, making it ideal for power supplies in AI data centers.

Lithium-manganese-rich (LMR) cathodes are an emerging high-capacity option for high-voltage operation, enabled by reversible lattice oxygen oxidation above about 4.5 V. They also use little to no cobalt, which lowers material cost and reduces environmental impact. To improve high-voltage stability at the cell level, fluorine has been widely introduced across the system, whether in the cathode, as an electrolyte additive, or within the lithium salt itself. But pushing the F content too high can raise HF generation, which becomes a safety risk for the cell. The safe upper limit for fluorine loading still isn’t well understood.

[1] Specific Capacity of Cathode Material Only

Source: Liu et al. Mater. Today 2016

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