Unified understanding and mitigation of detrimental phase transition in cobalt-free LiNiO2

• DOI: 10.1016/j.ensm.2024.103200
• Publication Date: 2024-01-18T20:49:32Z
• Authors: Itsuki Konuma; Naohiro Ikeda; Benoît D.L. Campéon; Hinata Fujimura; Jun Kikkawa; Huu Duc Luong; Yoshitaka Tateyama; Yosuke Ugata; Masao Yonemura; Toru Ishigaki; Taira Aida; Naoaki Yabuuchi
• Keywords: Particle (ecology); Stoichiometry

Ni-enriched layered materials are used as electrode of Li-ion batteries for electric vehicle applications. Stoichiometric LiNiO2 with cationic Ni3+/Ni4+ redox is the ideal material, but gradual loss capacity at high voltage region, associated Ni ion migration, hinders its use practical Therefore, to improve reversibility LiNiO2, less abundant Co ions and/or other electrochemically inactive ions, e.g., Al3+ in part substituted ions. Nevertheless, a unified understanding improvement by metal substitution yet not established. In this study, origin causing detrimental phase transition discussed through detailed analysis on integrated nanosized Li3PO4 derived from metastable and rocksalt LiNiO2–Li3PO4 solid solution sample. oxide has approximately 6 % anti-site defects, particle size growth suppressed uniformly dispersed Li3PO4. low crystallinity partial structural disordering, migration tetrahedral sites effectively because repulsive electrostatic interaction Li layers. Moreover, these findings, non-stoichiometric Li0.975Ni1.025O2 smaller been directly synthesized without high-energy milling integration, significant achieved. Electrode further improved surface stabilization highly concentrated electrolyte solution. The deterioration mechanisms offers new criterion design Co-free substitution, leading full utilization reversible materials.