Z.I. Radzi, M.Z. Kufian, V. Balakrishnan, J. Selvaraj
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. © 2026 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences.
Higher Institution Centre of Excellence (HICoE), UM Power Energy Dedicated Advanced Centre (UMPEDAC), Universiti Malaya, Level 4, Wisma R&D, Jalan Pantai Baharu, Kuala Lumpur, 59990, Malaysia; Centre for Ionics University of Malaya (CIUM), Physics Department, Faculty of Science, Universiti Malaya, Kuala Lumpur, 50603, Malaysia; Department of Mathematical Sciences, Saveetha School of Engineering, SIMATS, Tamil Nadu, Chennai, 602105, India; Department of Electrical Engineering, Faculty of Engineering, Universitas Negeri Padang, Padang, Indonesia
