Array structured NiAl-layered double hydroxides grown on graphene by atomic layer deposition as chloride-ion battery cathode

Abstract

Novel and promising chloride ion batteries (CIBs) that can operate at room temperature have attracted great attentions, due to the sustainable chloride-containing resources and high theoretical energy density. To achieve the superior electrochemical properties of CIBs, the structure design of electrode materials is essential. Herein, 2D NiAl-layered double hydroxide (NiAl-LDH) nanoarrays derived from Al₂O₃ are in-situ grafted to graphene (G) by atomic layer deposition (ALD) and hydrothermal method. The achieved NiAl-LDH@G hybrids with 2D NiAl-LDH arrays grown perpendicularly on graphene surface, can efficiently prevent the stacking of LDHs and enlarge specific surface area to provide more active sites. The NiAl-LDH@G cathode exhibits a maximum discharge capacity of 223.3 ​mA ​h g⁻¹ and an excellent reversible capacity of 107 ​mA ​h g⁻¹ over 500 cycles at 100 ​mA ​g⁻¹ with a high coulombic efficiency around 96 ​%, whereas pure NiAl-LDH has a discharge capacity of only 48.8 ​mA ​h g⁻¹ and a coulombic efficiency (CE) of about 78 ​%. More importantly, the NiAl-LDH@G electrode has a stable voltage at 1.9 ​V and an outstanding discharge capacity of higher than 72 ​mA ​h g⁻¹ after 120 days. Additionally, XRD, XPS, and EDS have been employed to unveil the electrochemical reaction and Cl⁻ storage mechanism of the NiAl-LDH@G cathode in CIBs. This work opens a facile and reasonable way for improving electrochemical performance at anion-type rechargeable batteries in terms of cathode material design and mechanism interpretation.