Self-assembled high-entropy Prussian blue analogue nanosheets enabling efficient sodium storage

High entropy material (HEM) has emerged as an appealing material platform for various applications, and specifically, the electrochemical performances of HEM could be further improved through self-assembled structure design. However, it remains a big challenge to construct such high-entropy self-assemblies primarily due to the compositional complexity. Herein, we propose a bottom-up directional freezing route to self-assemble high-entropy hydrosols into porous nanosheets. Taking Prussian blue analogue (PBA) as an example, the simultaneous coordination-substitution reactions yield stable high-entropy PBA hydrosols. During subsequent directional freezing process, the anisotropic growth of ice crystals could guide the two-dimensional confined assembly of colloidal nanoparticles, resulting in high-entropy PBA nanosheets (HE-PBA NSs). Thanks to the high-entropy and self-assembled structure design, the HE-PBA NSs manifests markedly enhanced sodium storage kinetics and performances in comparison with medium/low entropy nanosheets and high entropy nanoparticles.