Influence of graphene wrapped-cerium oxide coating on spherical LiNi0.5Mn1.5O4 particles as cathode in high-voltage lithium-ion batteries

Abstract

Cobalt-free LiNi 0.5 Mn 1.5 O 4 (Lithium Nickel Manganese Oxide; LNMO) has garnered considerable interest as a cathode material due to its high working voltage, lower cost, and environmental friendliness. However, LNMO cathodes currently exhibit low cyclability and capacity deterioration, severely restricting their use on a broader scale. To this end, microwave-assisted chemical co-precipitation was used to produce spherical aggregated nanoparticles of LiNi 0.5 Mn 1.5 O 4 (LNMO) coated with CeO 2 (LNMO-Ce) and wrapped in graphene (LNMO-Ce-GO). Structural analysis demonstrates that the ceria coating along with the graphene wrapping prevents unwanted phases from forming and altering the morphology of the LNMO microspheres. LNMO-Ce-GO exhibits a discharge capacity of 132.4 mAhg −1 at the C/10 rate with a capacity retention of 95.3 % after 100 cycles, compared to LNMO-Ce and bare LNMO samples that provide a capacity retention of 91.6 % and 84.7 % respectively. DSC analysis elucidate that the ceria coating helps to suppress the adverse reactions at the electrode/electrolyte interface and reduce the Mn 3+ dissolution due to the Jahn Teller effect, increasing cell cyclability. The graphene wrapping reduces material aggregation and provides conductive pathways that significantly improve the electrochemical performance of the LNMO cathode. This innovative material design strategy can be efficiently expanded to other classes of lithium-ion battery cathode materials to enhance their electrochemical performance. • Graphene wrapped ceria coated LiNi 0.5 Mn 1.5 O 4 was synthesized utilizing microwave-assisted chemical co-precipitation technique. • SEM analysis illustrates the formation of secondary spherical microspheres with primary nanoparticles of LiNi 0.5 Mn 1.5 O 4 . • TEM analysis exhibits a 1–3 nm ceria coating and graphene wrapping over LiNi 0.5 Mn 1.5 O 4 particles. • Surface-modified disordered LNMO exhibits improved cyclability with a 98.6 % capacity retention after 100 cycles at C/10 rate. • Graphene wrapping & ceria coating reduces interfacial resistance and increases lithium-ion diffusion kinetics.