Compositionally complex ball-in-ball type metal oxide anode via laser-induced fast fabrication for binder-free high-capacity Li-ion batteries

Abstract

This study focuses on addressing the limited cycleability challenge of conversion-type anodes in rechargeable lithium-ion batteries (LIBs) by utilizing new high entropy materials with innovative fabrication techniques. This is the inaugural exploration of first-row transition metals (Fe, Co, Ni, Mn, Cr) composed in an entropically stabilized glycerate form (HEG) as an efficient LIB anode with a high reversible capacity exceeding 500 mAh/g (0.1 A/g) over 270 cycles. Further, we demonstrate an innovative rapid conversion of the HEG to a spinel phase high entropy oxide (HEO) via a CO2 laser treatment and demonstrate the fabrication of a binder-free anode comprising laser-induced reduced graphene oxide (rGO) and HEO ((Fe0.45Co0.14Ni0.2Cr0.13Mn0.08)3O4) composites. The composite (HEO@rGO) showed a high specific capacity of ~794 mAh/g (0.1 A/g) after 100 cycles and a specific capacity of ~530 mAh/g (0.5 A/g) after 200 cycles. These results surpass the performance of many previous reports on high entropy materials. The charge storage mechanism demonstrated the persistence of the spinel structure within HEO, accompanied by a partial transformation towards a rock salt configuration. The undulating nature of the cycling stability profile was found to be linked with a variation in charge transfer resistance and lithium diffusion with cycling.