Layered double hydroxide-derived Fe-doped NiSe cathode toward stable and high-energy aluminum storage

Rechargeable aluminum-ion batteries (AIBs) are promising candidates for energy storage because of their low cost, high safety, and high-power density owing to the three-electron redox reaction. However, the applications of AIBs are hindered by their limited lifetime and practically achievable energy density. Herein, we present a novel Fe-doped Nickel selenide (Fe-NiSe) nanoflake cathode material, derived from a Ni–Fe layered double hydroxide, affording a long cycle life and high energy density. Synergism between the ultrafine nanostructure and Fe doping provided shorter ion diffusion pathways and created multiple active sites in the cathode. As a result, the prepared Fe–NiSe battery achieved an outstanding energy density of 402.5 W h kg−1 and an ultra-long lifespan of 13,500 cycles with a capacity decay of only 0.0026% per cycle. Furthermore, based on the mass of the entire pouch-type cell, the fabricated AIB delivered an energy density of 101.2 W h kg−1. This work paves the way for serviceable high-energy density AIBs.