Understanding initial capacity loss in substituted layered oxide cathodes for lithium-ion batteries

<p>Layered oxide LiCoO₂ (LCO) pioneered the commercialization of lithium-ion batteries (LIBs) in 1991, yet the growing demand for higher energy density has driven the development of substituted layered oxides, including LiNiᵧMn𝓏Co₁₋ᵧ₋𝓏O₂ (NMC) and LiNiᵧCo₁₋ᵧ₋𝓏Al𝓏O₂ (NCA). Despite the increased energy density, achieving full lithium reversibility during the first charge-discharge cycle remains a critical challenge: approximately 0.08–0.11 Li is “irreversibly” lost after delithiation, resulting in a substantial capacity loss of 10–15%. This loss is conventionally attributed to bulk lithium transport limitations arising from three interrelated factors: (1) contraction of the c-axis lattice during lithiation, (2) reduced rate of tetrahedral site hopping (TSH) at high lithium concentrations, and (3) localized charge accumulation near low-valent transition metal (TM) ions. This work challenges this view, demonstrating that initial capacity loss (ICL) stems from a complex interplay of bulk, surface, and interfacial kinetics rather than bulk transport alone. Electrochemical analysis of LiNiᵧCo₁₋ᵧO₂ (0 ≤ y ≤ 0.80) and ternary NMC variants (NMC111, NMC525, NMC811) identifies compositional thresholds: systems with y ≤ 0.60 retain low ICL of 0.014–0.037 Li at a delithiation limit of 0.4 Li, whereas at y = 0.80, ICL surges to 0.081 Li. In ternary systems, simultaneous incorporation of Mn and Ni maintains low ICL, with no measurable influence of Mn on the observed capacity loss. Furthermore, increasing the delithiation limit in NMC811 from 0.4 Li to 0.8 Li reduces ICL by over 30%—from 0.137 Li to 0.094 Li—likely driven by decomposition of the surface impurity layer at high voltages. These findings refine our understanding of ICL in layered oxide cathodes and emphasize the need for holistic kinetic optimization across bulk, surface, and interfacial domains for maximizing first cycle performance.</p>

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Materials Science and Engineering

Year

2025

Authors dc:creator

• Wyco, Gy
• <p><a>https://orcid.org/0009-0007-1328-4910</a></p>

Contributors dc:contributor

• Dr. M. Stanley Whittingham

• Bulk diffusion
• Kinetic limitation
• Layered oxide cathode
• Lithium-ion batteries
• Materials Science and Engineering

Repository record dc:identifier

https://orb.binghamton.edu/dissertation_and_theses/437

OAI identifier oai:identifier

oai:orb.binghamton.edu:dissertation_and_theses-1443