Nickel-iron layered double hydroxides and reduced graphene oxide composite with robust lithium ion adsorption ability for high-capacity energy storage systems

Abstract

Rationally designed electrode materials with high capacity, excellent stability, and good rate capability are essential for high-performance energy storage systems. This study reported the design of nickel-iron layered double hydroxides nanosheets and reduced graphene oxide composites (NiFe-LDHs/rGO composites) for high-capacity LIB electrode. The NiFe-LDHs/rGO composites were prepared by adsorption of Ni2+ and Fe3+ ions onto the graphene oxide (GO) surface, co-deposition of NiFe-LDHs nanosheets from the adsorbed ions in alkaline solution, and reduction of GO into rGO. In the composites, a large interlayer spacing of 7.55 Å and proper adsorption energy for Li+ ion (−4.36 eV) in NiFe-LDHs nanosheets greatly facilitate the reversible transport and storage of abundant Li+ ions. Meanwhile, the outer rGO wrappings offer a highly conductive matrix as efficient electron pathways. With these advantages, the NiFe-LDHs/rGO composites demonstrated a good cyclic stability with 602.8 mAh g−1 capacity remained over 80 charge/discharge cycles at a current density of 500 mA g−1. Thus, our studies offer a low-cost NiFe-LDHs/rGO material for high-performance LIBs.