Calendering‐Dependent Electrochemical and Cost‐Energy Tradeoffs in Layered – Olivine Blend Cathodes

Abstract

Blended cathodes comprised of layered oxide and olivine materials, such as LiNi 0.9 Mn 0.05 Co 0.05 O 2 (NMC) and LiMn 0.7 Fe 0.3 PO 4 (LMFP), are appealing due to their reduced cost and enhanced safety, rate capability, and cyclability compared to high‐Ni layered oxides. However, while these blends are often discussed in terms of particle‐level properties, the effect of processing conditions, such as calendering, has received less attention, despite their strong influence on electrode microstructure due to the differences in morphology, surface characteristics, and crystallographic density. We investigate here systematically NMC, NMC/LMFP with 70/30 wt.%, and NMC/LMFP with 50/50 wt.% cathodes under uncalendered, moderately‐calendered, and hard‐calendered conditions, employing state‐of‐charge‐dependent rate analysis, full‐cell cycling, electrode‐level transport characterization, and cathode‐level cost‐energy evaluation. NMC tolerates calendering, maintaining rate capability, while showing improved capacity retention over 500 cycles. In contrast, NMC/LMFP blends show a narrower, composition‐dependent calendering limit. The 70/30 blend retains its rate‐capability benefit under no‐to‐moderate calendering, whereas the 50/50 blend is strongly penalized by densification. Hard calendering induces transport‐limited behavior in the blends, eliminating rate benefits and degrading cyclability. Stabilizing the NMC with Nb incorporation further improves cyclability and energy retention of the 70/30 blend, demonstrating a pathway to combine microstructure‐enabled rate capability with improved durability and favorable cathode‐level cost‐energy balance.