Decoupling morphology and facet effects on Li-ion transport kinetics and interfacial stability in spinel LiMn2O4 cathodes for high-voltage lithium-ion batteries--颗粒学报PARTICUOLOGY

Decoupling morphology and facet effects on Li-ion transport kinetics and interfacial stability in spinel LiMn₂O₄ cathodes for high-voltage lithium-ion batteries

Z.I. Radzi^a *, M.Z. Kufian^b, V. Balakrishnan^a, J. Selvaraj^{a c d *}

a Higher Institution Centre of Excellence (HICoE), UM Power Energy Dedicated Advanced Centre (UMPEDAC), Universiti Malaya, Level 4, Wisma R&D, Jalan Pantai Baharu, 59990, Kuala Lumpur, Malaysia
b Centre for Ionics University of Malaya (CIUM), Physics Department, Faculty of Science, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
c Department of Mathematical Sciences, Saveetha School of Engineering, SIMATS, Chennai, Tamil Nadu, 602105, India
d Department of Electrical Engineering, Faculty of Engineering, Universitas Negeri Padang, Padang, Indonesia

10.1016/j.partic.2026.06.011

Volume 116, September 2026, Pages 34-43

Received 4 May 2026, Revised 4 June 2026, Accepted 9 June 2026, Available online 16 June 2026, Version of Record 22 June 2026.

E-mail: jeyraj@um.edu.my

Highlights

• Morphology-facet interplay governs the rate-stability trade-off in spinel LiMn₂O₄ at 4.6 V operation.

• Nanostructured LiMn₂O₄ enhances Li ⁺ transport and high-rate electrochemical response.

• Facet-stabilized microstructured LiMn₂O₄ exhibits superior cycling and interfacial stability.

• Postmortem analyses reveal cracking and thick surface films in nanoscale LiMn₂O₄ at high voltage.

• Facet-engineered morphology offers a pathway to balance kinetics and durability in spinel cathodes.

Abstract

Spinel LiMn₂O₄ (LMO) is a promising cobalt-free cathode for high-voltage lithium-ion batteries, yet the interplay between particle morphology, crystallographic facet orientation, and electrochemical performance remains poorly understood. Here, we systematically decouple the morphology and facet-dependent determinants of the rate-stability trade-off by comparing hydrothermally synthesized nanostructured LMO (LMO-H) and commercial microstructured LMO (LMO-C) under an aggressive cut-off voltage of 4.6 V vs. Li/Li⁺. LMO-H, with an average particle size of ∼31 nm, delivers exceptional high-rate capability, retaining 61.4% capacity at 20C, among the highest reported for undoped spinel LMO, owing to dramatically shortened Li-ion diffusion pathways and superior Li diffusivity (up to 1.23 × 10⁻¹¹ cm² s⁻¹). However, this kinetic advantage is progressively offset by particle fracture and accelerated cathode electrolyte interphase (CEI) growth, resulting in 84.8% capacity retention at 1C after 100 cycles. By contrast, LMO-C, whose surface is dominated by thermodynamically stable {111} facets, nucleates a compact, self-limiting interphase that suppresses electrolyte decomposition, achieving an outstanding 90.2% capacity retention at 1C after 100 cycles. Postmortem SEM, EIS, and FTIR analyses confirm that uncontrolled interfacial reactions drive thick ROCO₂Li and Li₂CO₃ accumulation in LMO-H, whereas LMO-C preserves structural integrity under identical conditions. These findings establish a fundamental size-facet interplay governing the kinetic-stability balance in spinel LMO, offering actionable design guidelines for next-generation cathodes that concurrently optimize Li-ion transport and interfacial robustness.

Graphical abstract

Keywords

LiMn₂O₄; Hydrothermal synthesis; Morphology control; Facet engineering; High-voltage stability

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