Extreme mixing in nanoporous high-entropy oxides for highly durable energy storage

The ability to mix many different metal cations in a single-phase nanoscale oxide is critical for property adjusting and new material discovery. However, synthesizing multicomponent high-entropy oxides (HEOs) consisting of over ten metal cations remains a challenge due to dissimilarity and immiscibility among these elements. Herein, we explore the accommodation ability of AlNi-type and AlTi-type intermetallic phases and find that the AlNi-type phase is powerful to accommodate many different kinds metal elements. By chemically dealloying the Al from the multicomponent AlNi-type intermetallic phase, multicomponent spinel oxides such as 7-component (AlNiCoRuMoCrFe)O, 8-component (AlNiCoRuMoCrFeTi)O, 13-component (AlNiCoCrFeCuMoVTaNbHfZrTi)O, 16-component (AlNiCoCrFeCuMoTaNbHfZrTiRuVPdY)O et al., with nanoporous structure and poor crystallity are obtained. As a case study, we find that when applied in Li-ion battery anode, our 16-component nanoporous HEO exhibits a high capacity of ∼1141.2 mAh g after 290 cycles at 0.1 A g and excellent cycling stability. This study greatly expands the composition space of nanoscale HEOs and provides an interesting route for new materials discovery.