Topological Insulator Layered Bi₂Te₃ Based 3D-Printed Nanocarbon Electrode for Rechargeable Aqueous Ammonium-Ion Battery

Rechargeable aqueous ammonium-ion batteries (AIBs) hold great potential for sustainable energy storage due to their low cost, high safety, and outstanding electrochemical characteristics. However, their development is hindered by the limited availability of suitable anode materials. Herein, we propose for the first time the use of a topological insulator, bismuth telluride (Bi₂Te₃), as a novel anode material integrated onto a 3D printed nanocarbon electrode (3DpCE) for NH₄+ ion storage. Taking advantage of the 3D porous framework and the non-metallic nature of NH₄+ ions, Bi₂Te₃@3DpCE exhibits a higher discharge capacity of 128 mAh g−1 at 0.5 A g−1 with lower polarization, and better cycling stability compared to metallic ions such as Li+ and Na+. Through various ex-situ characterizations, we also reveal the plausible NH₄+ storage mechanism. A full cell based on a “rocking-chair” configuration is constructed using copper hexacyanoferrate (CuHCF) as the cathode. The CuHCF@3DpCE//Bi₂Te₃@3DpCE full cell in 1 M (NH₄)2SO₄ electrolyte delivers a high energy density of 134.8 Wh kg−1 and a power density of 1800 W kg−1, outperforming previously reported AIBs. Furthermore, the recyclability of the used 3D printed nanocarbon electrode is demonstrated, highlighting its eco-friendly potential. These findings offer a promising pathway toward high-performance, sustainable, next-generation AIB technologies.