Material Insights · Understanding the Material World

Nickel-rich lithium-ion batteries: Engineering and performance

Why grid builders traded compact NMC for safer LFP

What this tab covers Engineering and operating performance: round-trip efficiency, whether power and energy can be scaled separately, footprint and siting, and safety.

NMC matches LFP on efficiency and wins on compactness, but costs more and carries higher fire risk, so grid buyers have mostly moved to LFP; LTO fills niches that need high power and many cycles.

Round-trip efficiency

Favourable

Efficiency is similar across lithium-ion types. The 2020 US assessment used about 86% for a complete lithium-ion system, and NREL uses 85% for utility plants. IRENA puts lithium-ion at 85 to 95%. No independent round-trip efficiency figure for LTO was found; its strength is accepting very high charge and discharge currents, with Toshiba citing about 80% charge in 6 minutes.6131416

Lithium-ion system efficiency (2020) about 86%6 NREL ATB utility assumption 85%13 Lithium-ion range (IRENA) 85-95%14 LTO fast charge (Toshiba SCiB) about 80% in 6 minutes16

Power and energy decoupling

Mixed

As with any cell battery, energy and power grow together with the number of cells, with only the inverter and grid connection sized separately. In the 2022 US assessment a 100 MW, 4-hour NMC plant cost USD 435/kWh installed against USD 385/kWh for LFP; at 10 hours the figures were USD 405 and USD 356. NMC's higher cost per kWh makes longer durations relatively more expensive.7

Installed cost, 100 MW 4 h, NMC vs LFP (2021) USD 435 vs 385/kWh7 Installed cost, 100 MW 10 h, NMC vs LFP (2021) USD 405 vs 356/kWh7

Footprint and siting flexibility

Mixed

NMC and NCA are the most compact lithium-ion options, which suits vehicles and space-limited buildings. For grid storage the space saving rarely outweighs LFP's cost and safety advantages, and LFP now takes over 90% of storage installations. LTO is bulky for its energy but small for its power.214

Lithium-ion volumetric energy density (IRENA) 200-700 kWh/m314 LFP share of storage installations (2025) over 90%2

Safety and thermal runaway risk

Unfavourable

Layered oxide cathodes become unstable above about 4.2 V, and nickel-rich versions are less stable still, so they release oxygen sooner in a fault and burn hotter than LFP. NMC storage must meet NFPA 855, whose 2026 edition requires large-scale fire tests showing no spread between units, and UL 9540A edition 6 from 1 January 2027. LTO is regarded as the safest lithium-ion type: its anode does not grow lithium metal, and Toshiba says that in an internal short the titanate turns highly resistive, limiting current, so fire and explosion risk is low (a manufacturer claim).6101115

Voltage above which layered cathodes destabilise about 4.2 V6 NFPA 855 threshold for lithium-ion 20 kWh10 UL 9540A edition 6 effective 1 January 202711

Sources

  1. Global EV Outlook 2026: Electric vehicle batteries International Energy Agency, 2026
  2. Lithium-ion Battery methodology, 2020 Grid Energy Storage Technology Cost and Performance Assessment PNNL / US DOE, 2020
  3. 2022 Grid Energy Storage Technology Cost and Performance Assessment US DOE / PNNL, 2022
  4. NFPA 855: 2026 edition updates and what they mean for energy storage projects Energy-Storage.news, 2026
  5. Understanding UL 9540A and NFPA 855 UL Solutions, 2026
  6. Annual Technology Baseline 2025: Utility-Scale Battery Storage National Laboratory of the Rockies (formerly NREL), 2025
  7. Sodium-ion batteries: Technology brief IRENA, 2025
  8. SCiB Rechargeable Battery catalogue (company data) Toshiba, 2019
  9. SCiB Battery Business (company claims) Toshiba Asia, 2025