One-pot preparation of La(OH)3 nanoparticles and NiMn LDH nanosheets with mutual support structure as cathode for high-performance aqueous zinc-ion batteries

Abstract

Aqueous zinc-ion battery (ZIB) is a promising electrochemical energy storage device, which combines high safety and low cost of water-based batteries, as well as the advantages of high theoretical capacity and low redox potential. In this work, a transition metal hydroxide material (La(OH) 3 /NiMn LDH) with a composite structure of nanosheets and nanoparticles has been synthesized by a simple hydrothermal reaction. In the electrochemical process, different structures support and restrict each other, which improves the stability of the structure while also buffering the volume shrinkage/expansion during the electrochemical process. The combination of NiMn LDH and La(OH) 3 is also in favor of material’s conductivity. Used as ZIBs cathode material, the La(OH) 3 /NiMn LDH composite structure achieves a better electrochemical performance than the single structure of other hydroxides. It’s specific capacity of the La(OH) 3 /NiMn LDH electrode can reach 284.2 mA h g -1 at the current density of 1 A g -1 . Furthermore, at higher current density of 5 A g -1 , 106.3 mA h g -1 of specific capacity is retained. At the same time, the hydroxyl on hydroxide surface and water molecules in the aqueous electrolyte will undergo surface remodeling, stabilize H + at the electrode and electrolyte interface, and promote the diffusion of H + into the material, thereby the electrochemical performance can be enhanced. • Multiple metal hydroxides are compounded together by one-pot hydrothermal method. • La(OH) 3 /NiMn LDH has a composite structure of nanosheets and nanoparticles. • The capacity of La(OH) 3 /NiMn LDH is 284.2 mA h g -1 at 1 A g -1 . • The La(OH) 3 /NiMn LDH cathode displays high energy density of 411.5 Wh kg -1 .