Self-Sacrificial Templated Lithium Manganese Oxide as a Longevous Cathode: The Intermarriage of Oxygen Defects and Zeolitic Imidazolate Framework Glass

Abstract

Spinel LiMn2O4 is a promising cathode material for lithium-ion batteries (LIBs) due to its nontoxicity, resource abundance, substantial operating voltage, and remarkable thermal stability. Nevertheless, LiMn2O4 is subjected to subpar electronic/ion conductivity and continuous capacity attenuation triggered by the Jahn-Teller distortion. In this regard, metal-organic frameworks (MOFs) are potential morphological controllers that impact particle size and crystal orientation and offer vacancy-accepting layers that facilitate oxygen defect formation, which boost electron/ion diffusion when utilized as self-sacrificial templates. The dissatisfying capacity retention caused by Mn2+ dissolution related to the Mn3+ disproportion is another tricky issue, which requires resolution through surface modification. To attain these goals, this work develops a strategy intermarrying the merits of oxygen defects and Zn-based zeolitic imidazolate framework-62 (Zn-ZIF-62) glass shields. Mn-MOFs with carboxyl-based ligands possessing various coordination numbers are adopted as precursors to optimize the morphological feature and modulate the oxygen vacancy level. Computational and experimental results examine the efficaciousness of oxygen defects in ameliorating the electrochemical activity and expediting electron/ion transportation. Synchronously, the ZIF-62 glass layer inhibits manganese loss and phase degradation toward prolonged cycling durability in LIB half/full cells. This study envisions a versatile methodology to modify spinel LiMn2O4 as a longevous cathode for next-generation LIBs.