High-Nickel Cathodes: What Is the Price of Energy Density?

What Is in Focus: The Trade-off Behind the Nickel Number

Raising the nickel content of a cathode improves energy density, but the price paid in thermal stability and cycle life grows with it. The real competitiveness of a high-nickel cathode is therefore decided not by a number such as “80% nickel” but by the particle-structure and surface-coating technologies that show how far that price has been reduced. This piece lays out the trade-off hidden behind the word “high-nickel” and the patent landscape around it.

Start with the industry picture. NCM (nickel-cobalt-manganese ternary) cathodes have moved toward higher nickel and lower cobalt, as in the shift from NCM 622 (60% nickel) to NCM 811 (80% nickel). Cobalt is an expensive raw material with high supply-chain risk, so the strategy of raising nickel to increase capacity while cutting cobalt targets cost and energy density at the same time.

The tension lies in a result the academic literature has shown repeatedly. A 2013 NCM composition comparison study published in the Journal of Power Sources reported that as nickel content increases, discharge capacity and residual lithium rise, while capacity retention and safety characteristics gradually decline. This piece answers three questions. What does nickel content change? What technologies reduce that price? And what scope of rights do those complementary technologies form from a patent perspective?

Basic Principle: Why More Nickel Means Less Stability

An NCM cathode has a layered oxide structure. Lithium layers and transition-metal (nickel, cobalt, manganese) layers are stacked alternately with oxygen between them; lithium leaves on charge and returns on discharge. Nickel is the main player in exchanging electrons, so the more nickel there is, the more lithium can be inserted and extracted per unit weight, and the larger the capacity.

The problem is bond strength. A 2020 review of high-nickel cathodes published in Energies summarized that increasing nickel concentration is accompanied by lower structural and thermal stability because of weaker Ni–O bonds. When temperature rises in the charged state, the crystal structure becomes unstable and releases oxygen more easily, and the released oxygen reacts with the electrolyte to raise thermal-runaway risk. A 2014 study in ACS Applied Materials & Interfaces, which observed charged NCM while heating it, likewise reported that the ratio of nickel, cobalt, and manganese strongly governs structural change and oxygen-release behavior.

By analogy, nickel is “a cargo hold that carries more but has a thinner floor.” It can carry more cargo (lithium), but when the shock of heat arrives, the floor warps first. Cobalt and manganese act as partitions and reinforcement, so the more cobalt is cut to lower cost, the more reinforcement is removed as well.

• What more nickel gives: higher discharge capacity (mAh/g), less cobalt (lower cost and supply-chain risk)
• What more nickel takes: thermal stability, capacity retention (life), and headroom in residual-lithium control

Comparison: NCM 622 vs. NCM 811

The table below preserves the original comparison table and adds the molar ratios read directly from the composition names, along with trends reported in the academic literature. Exact capacities and exothermic onset temperatures by composition vary with synthesis conditions and measurement methods, so this piece shows only direction.

Item	NCM 622 (60% nickel)	NCM 811 (80% nickel)
Transition-metal molar ratio (Ni:Co:Mn)	6:2:2	8:1:1
Energy density	Moderate	High
Discharge capacity (mAh/g) trend	Relatively lower	Rises with nickel content
Thermal stability	Relatively better	Lower (exothermic onset temperature drops)
Capacity retention (life) trend	Relatively favorable	Falls with nickel content
Residual lithium	Relatively less	Increases with nickel content
Cobalt usage	High (20% of transition metals)	Low (10% of transition metals; lower cost and supply-chain risk)

What this table says: Raising nickel from 60% to 80% halves cobalt from 20% to 10% and increases capacity, but thermal stability, life, and residual lithium all become less favorable at once. In other words, moving to high nickel trades “one gain for three management challenges.”

So what are the complementary technologies? The two directions the original piece pointed to are single-crystal particles and surface coating. A conventional cathode consists of polycrystalline secondary particles made of agglomerated small primary particles; when microcracks form at the boundaries between particles during cycling, electrolyte seeps in and side reactions increase. The 2020 review cited above explains that single-crystal particles minimize the risk of microcracking, a cause of shortened cycle life. Surface coating applies a thin protective layer to the particle surface to reduce direct contact with the electrolyte.

Here this piece adds one interpretation. Nickel content is written as a single line on a spec sheet, but the level of single-crystallization and coating is rarely disclosed. So even the same “NCM 811” can have different life and safety margins from supplier to supplier, and the real variable that procurement and planning staff should compare is not the nickel number but the “package of complementary technologies.” As nickel content rises, the center of gravity of competition can be seen as shifting from composition to process and surface technology.

Patent Perspective: The Scope of Rights Created by Coating Claims

Claim gist: As an example of how high-nickel complementary technology is claimed, consider US granted patent US9118075B2 (Cathode active material for lithium secondary battery), filed by LG Chem. According to Google Patents, its priority date is January 6, 2009, its filing date July 9, 2010, and its grant date August 25, 2015; the rights were assigned to LG Energy Solution on November 4, 2021, and its legal status is shown as Active (anticipated expiration November 12, 2031). In substance, claim 1 covers a cathode active material that is a lithium nickel-manganese-cobalt oxide of the form LixMyO2 with nickel at 40-90% of the transition metals, manganese at 5-40%, and cobalt at 10-40%, with a lithium phosphate (Li₃PO₄) coating on the surface at a weight ratio of 100:1 to 100:2 relative to the active material.

Filing history: The same applicant, with the same priority date (January 6, 2009), also claimed in US8329339B2 (granted December 11, 2012; Active; anticipated expiration May 8, 2030) a configuration in which a polymer coating such as polyethylene or polypropylene is placed on the surface of a lithium nickel oxide with nickel in the 40-90% range. Securing two parallel branches of rights from one priority date, inorganic phosphate coating and polymer coating, reads as a filing approach that splits the idea of blocking high nickel’s weakness “at the surface” into separate rights by coating material.

Design-around points: Coating claims layer several limitations, composition range, coating material, and weight ratio, so the scope of rights may be narrower than it seems. For example, the cobalt lower bound in US9118075B2 is 10%, so NCM 811 (10% cobalt) sits on the boundary, while a composition that cuts cobalt below 10% may fall outside the literal scope. Replacing lithium phosphate with a different coating compound or setting the weight ratio outside the claimed range could also be ways to avoid literal infringement.

Design-around scenario (counterargument): However, if another phosphate or a similar inorganic coating achieves the same purpose (suppressing electrolyte side reactions) with the same effect, it may be subject to a doctrine-of-equivalents analysis, so it is hard to conclude that swapping the coating material alone eliminates infringement risk. Moreover, cutting cobalt below 10% may avoid the claim but further worsens the thermal-stability loss discussed above, so the design-around itself demands new complementary technology (single-crystallization or a different coating) and creates a loop in which FTO (freedom-to-operate, infringement review) must be rechecked against third-party patents on that technology.

Limits and Outlook

The optimistic outlook is that as single-crystal and coating technologies mature, nickel content can be raised further while securing safety and life, and cobalt dependence can keep falling. There is, however, a counter-scenario. The higher the nickel content, the greater the process cost and quality-control burden of complementary technologies, so the cost gain from cutting cobalt may be offset by higher process costs. In that case the assumption that “the more nickel, the better” breaks down, and a mid-nickel composition may become the more rational choice in cost-performance terms. The 2014 study’s assessment of NMC532 as a balance point between thermal stability and capacity is consistent with this view.

The strategic alternative is to evaluate composition and complementary technology as a single bundle. When comparing suppliers, putting nickel content alongside particle morphology (single-crystal or polycrystalline), coating material, and residual-lithium control level in the same table reduces the risk of overestimating the safety margin by looking only at energy-density figures. The high-nickel cathode is where energy density and thermal stability collide head-on, and real performance can only be gauged by looking not just at the nickel number but also at the particle-structure and coating technologies that compensate for it.

Practical action: Planning and IP staff considering high-nickel cathodes should list each candidate material’s cobalt content (at or above vs. below 10%), coating material, and coating weight ratio, and build a claim chart against in-force patents that limit both composition range and coating material, such as US9118075B2 and US8329339B2, as the starting point for FTO review.

Items requiring verification

• Comparative figures, under identical conditions, for representative discharge capacity (mAh/g) and DSC exothermic onset temperature (°C) of NCM 622 and NCM 811
• Grant status and claim-scope differences of the Korean, European, and other family counterparts of US9118075B2 and US8329339B2
• Major applicants and in-force patents related to single-crystal high-nickel cathodes

Sources

1. H.-J. Noh, S. Youn, C. S. Yoon, Y.-K. Sun, Journal of Power Sources 233 (2013) 121-130 – Comparison of the structural and electrochemical properties of layered Li[NixCoyMnz]O2 cathode material
2. C. M. Julien, A. Mauger, Energies 2020, 13(23), 6363 – NCA, NCM811, and the Route to Ni-Richer Lithium-Ion Batteries
3. S.-M. Bak et al., ACS Applied Materials & Interfaces (2014) 22594-22601 – Structural changes and thermal stability of charged LiNixMnyCozO2 cathode materials
4. Google Patents, US9118075B2 – Cathode active material for lithium secondary battery
5. Google Patents, US8329339B2 – Cathode active material for lithium secondary battery

Related Reading — LFP vs. NCM: Not Better or Worse, Just Different Optimization Axes · Electrolytes, From Liquid to Solid — The Trade-off Between Safety and Interface Resistance · Silicon Anode Materials — Why Only Small Amounts Are Still Blended In: The Volume-Expansion Wall and 2026 Commercialization Trends