Co3O4/LaCoO3 nanocomposites derived from MOFs as anodes for high-performance lithium-ion batteries

Abstract

• The lanthanide perovskite LaCoO 3 is synthesized from pyrolysis of MOF. • The introduction of LaCoO 3 improves the lithium storage performance and structural stability of Co 3 O 4 . • The capacitance contribution rate of the composite material reached an incredible 94.7% at 1.0 mV/s. Co 3 O 4 has been extensively studied due to its high theoretical capacity in lithium ion batteries (LIBs) anode materials. Unfortunately, the large volume change of Co 3 O 4 during charging and discharging causes severe capacity degradation, which limits its practical application. In this paper, the metal organic framework (MOF) synthesized by the microwave method was used as the precursor, and the Co 3 O 4 /LaCoO 3 nanocomposite with unique heterostructure was synthesized by calcination. The introduction of LaCoO 3 improves the lithium storage performance and structural stability of Co 3 O 4 . Under the best doping ratio, the reversible charging capacity of Co 3 O 4 /LaCoO 3 reaches 1024 mAh/g (after 100 cycles), breaking the theoretical capacity limit of Co 3 O 4 . Impressively, even at a high current density of 1 A/g, the composite electrode still exhibits an ultra-high reversible capacity of 799 mAh/g. The excellent electrochemical performance of Co 3 O 4 /LaCoO 3 is attributed to the introduction of LaCoO 3 which provides a buffer space for electrode volume changes and shortens the diffusion path of Li + . Finally, kinetic analysis shows that the capacity and stability enhancement mechanism is related to the ultra-high capacitance ratio of the composite material (94.7% at 1 mV/s). This study demonstrates a MOF in-situ synthesis project: a way to overcome the capacity and cycle limitations of Co 3 O 4 in LIBs anodes by compounding lanthanide perovskites.