Lithium-manganese-rich (LMR)

State of the art (2026)

The defining event is GM and LG Energy Solution’s May 2025 commitment to commercialise LMR prismatic cells, targeting mass production at Ultium Cells in 2028 with pre-production at an LGES plant in late 2027. GM claims 33% higher energy density than the best LFP cells at comparable cost, aimed at full-size electric trucks and SUVs such as the Silverado EV and Escalade IQ. This is the first credible production timeline after two decades of laboratory results. CATL’s 500 Wh/kg condensed-matter cell remains aviation-focused, while Samsung SDI and Toyota pursue solid-state LMR. Voltage fade – the layered-to-spinel structural collapse that bleeds capacity over cycling – is still the unsolved barrier between LMR’s ceiling and a shipped product.

LMR is the highest-ceiling chemistry in lithium-ion — if the floor can be raised

Lithium-manganese-rich cathodes (xLi2MnO3·(1-x)LiMO2 where M = Ni, Co, Mn) deliver 250-300 mAh/g specific capacity versus 180-210 for NMC811, translating to 350-400 Wh/kg at cell level. This 30-50% energy density advantage would extend EV range from 300 miles to 450+ miles on the same pack volume, or reduce pack size (and cost) by 30% for the same range. Critically, LMR uses primarily manganese — 300x more abundant than cobalt and 10x cheaper than nickel. If LMR works, it simultaneously solves the energy density and material cost challenges of lithium-ion. The chemistry has been known since 2001 (Thackeray, Argonne). Twenty-three years of research have improved it significantly but not enough.

Voltage fade is a structural transformation problem, not just a surface problem

LMR's voltage fade occurs because the cathode crystal structure irreversibly transforms from a layered configuration (desirable, high voltage) to a spinel configuration (undesirable, lower voltage) during cycling. This transformation begins at the particle surface and propagates inward. Surface coatings (Al2O3, TiO2, LiNbO3) slow but do not stop the transformation. Electrolyte additives reduce side reactions that accelerate the transition but cannot prevent the thermodynamic driving force toward spinel formation. The most promising approaches — cation-disordered rock salt structures and high-entropy compositions — represent a fundamental redesign rather than an incremental fix. This suggests that commercially viable LMR will be a different material than the LMR studied for the past two decades.

Three major programs (CATL, Samsung SDI, GM) will determine LMR's fate by 2028

CATL's condensed-matter battery program, Samsung SDI's all-solid-state LMR approach, and GM's Ultium LMR development represent the three most serious commercial LMR programs. Each takes a different approach to the voltage fade problem: CATL uses electrolyte engineering, Samsung SDI uses solid-state electrolyte to suppress surface reactions, and GM uses surface coating and BMS compensation. If any of these programs announces production-intent LMR cells with less than 5% voltage fade over 1,000 cycles, it triggers an industry-wide shift to LMR. If all three programs stall or downscale, LMR is effectively dead for this generation of EVs.