Solid-state synthesis of β-NaAlO2 nanoflakes as an anode material for high-performance sodium-ion batteries

Abstract

New anode materials for sodium-ion batteries are being extensively studied to achieve high stability and long-term cyclability. In this work, we demonstrate the solid-state synthesis of β-NaAlO₂ nanoflakes as a high performance, long-life anode material for sodium-ion batteries (SIBs). The β-NaAlO₂ nanoflakes exhibit a theoretical capacity of ∼326.69 mA h g⁻¹. The as-assembled SIB with β-NaAlO₂ as the anode material exhibits an initial discharge capacity of ∼318 mA h g⁻¹ at 0.1C-rate (1st cycle). The SIB displays a discharge capacity of ∼183 mA h g⁻¹ after 1000 cycles with a coulombic efficiency of 92%. This outstanding performance with the long-term cyclability of the β-NaAlO₂ anode can be ascribed to the Al³⁺ in the structure that reduces the Jahn–Teller distortion effect during the process of sodiation and desodiation cycles. The good cyclability of the β-NaAlO₂ anode proves it to be a highly stable and cost-effective anode material for high-energy SIBs.