Microstructure–Driven Degradation Mechanisms in High-Nickel NMC Cathodes for Lithium-Ion Batteries
4 affiliations
- 1Max Planck Institute for Sustainable Materials
- 2Indian Institute of Technology Ropar
- 3School of Materials Science and Engineering
- 4Shanghai Jiao Tong University
Abstract
Mechanical degradation in high-nickel layered oxide cathodes is closely associated with anisotropic lattice-parameter changes during electrochemical cycling, yet how cathode microstructure size influences the resulting crystallographic deformation remains poorly understood. Here, we investigate two LiNi0.90Mn0.05Co0.05O2 (NMC955) cathodes with comparable secondary-particle sizes but different average grain sizes (1.0 and 0.5 µm). The fine-grained cathode delivers 30% higher initial discharge capacity, 40% lower voltage polarization, improved rate capability, and 13% higher capacity retention after 100 cycles. Despite its superior electrochemical performance, the fine-grained material exhibits approximately 1.23 times higher mean kernel average misorientation after 100 cycles, together with higher estimated geometrically necessary dislocation density, indicating greater average local lattice curvature. The coarse-grained cathode shows pronounced localization of crystallographic misorientation near grain boundaries and secondary-particle peripheries, whereas the fine-grained cathode exhibits a more spatially distributed misorientation response. Complementary chemo-mechanical simulations reproduce the grain-size-dependent trends in lattice curvature and reveal differences in the spatial distribution of plastic strain associated with the different grain sizes. After 100 cycles, the coarse-grained cathode undergoes extensive intergranular cracking and secondary-particle fragmentation, while the fine-grained cathode largely preserves its structural integrity. These findings identify the spatial localization of cycling-induced crystallographic misorientation, rather than its average magnitude alone, as a pivotal variable for electrode design.
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BibTeX
@misc{dammak2026microstructuredriven,
title = {{Microstructure–Driven Degradation Mechanisms in High-Nickel NMC Cathodes for Lithium-Ion Batteries}},
author = {Yosra Dammak and Soroush Motahari and Mahander Pratap Singh and Adam Miles and Poonam Yadav and Pradhyun Veerapanaicker Soundaraj and Stefan Zaefferer and Dierk Raabe and Chuanlai Liu and Yug Joshi},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15010466/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010466/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Microstructure–Driven Degradation Mechanisms in High-Nickel NMC Cathodes for Lithium-Ion Batteries
AU - Yosra Dammak
AU - Soroush Motahari
AU - Mahander Pratap Singh
AU - Adam Miles
AU - Poonam Yadav
AU - Pradhyun Veerapanaicker Soundaraj
AU - Stefan Zaefferer
AU - Dierk Raabe
AU - Chuanlai Liu
AU - Yug Joshi
PY - 2026
DA - 2026/10/14
PB - ChemRxiv
DO - 10.26434/chemrxiv.15010466/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010466/v1
AB - Mechanical degradation in high-nickel layered oxide cathodes is closely associated with anisotropic lattice-parameter changes during electrochemical cycling, yet how cathode microstructure size influences the resulting crystallographic deformation remains poorly understood. Here, we investigate two LiNi0.90Mn0.05Co0.05O2 (NMC955) cathodes with comparable secondary-particle sizes but different average grain sizes (1.0 and 0.5 µm). The fine-grained cathode delivers 30% higher initial discharge capacity, 40% lower voltage polarization, improved rate capability, and 13% higher capacity retention after 100 cycles. Despite its superior electrochemical performance, the fine-grained material exhibits approximately 1.23 times higher mean kernel average misorientation after 100 cycles, together with higher estimated geometrically necessary dislocation density, indicating greater average local lattice curvature. The coarse-grained cathode shows pronounced localization of crystallographic misorientation near grain boundaries and secondary-particle peripheries, whereas the fine-grained cathode exhibits a more spatially distributed misorientation response. Complementary chemo-mechanical simulations reproduce the grain-size-dependent trends in lattice curvature and reveal differences in the spatial distribution of plastic strain associated with the different grain sizes. After 100 cycles, the coarse-grained cathode undergoes extensive intergranular cracking and secondary-particle fragmentation, while the fine-grained cathode largely preserves its structural integrity. These findings identify the spatial localization of cycling-induced crystallographic misorientation, rather than its average magnitude alone, as a pivotal variable for electrode design.
ER -