Extrinsic pseudocapacitive ultrathin 2D MoS2 nanoflakes clamped on 1D Sb2S3 nanorods: an advanced heterostructured anode for high-energy ammonium ion hybrid capacitors

Abstract

Ammonium-ion (NH₄⁺) charge carriers have recently been considered promising for electrochemical energy storage (EES) systems because of their high safety, low molar mass, and small hydrated radius (3.31 Å). However, finding a kinetically balanced anode and cathode combination for high NH₄⁺-ion storage is challenging. Herein, a new approach for developing a heterostructured electrode was developed by constructing extrinsic pseudocapacitive 2D ultrathin MoS₂ nanoflakes clamped on 1D Sb₂S₃ nanorods (MoS₂/Sb₂S₃) as an anode for high-performance ammonium-ion hybrid capacitors (AIHCs) against the intrinsic pseudocapacitive MnO₂ cathode. The engineered MoS₂/Sb₂S₃ heterostructured anode facilitated large interlayer galleries owing to the presence of 2D MoS₂ for facial NH₄⁺-ion diffusion and provided a rapid electron pathway through 1D Sb₂S₃, which promoted a high capacitance of 360 F g⁻¹, low resistance, and stable cycling performance. More importantly, the constructed AIHC delivered a superior energy density of 43.75 W h kg⁻¹ at a power density of 600 W kg⁻¹ and excellent cycling durability over 5000 cycles. These results show that a heterostructured extrinsic pseudocapacitive anode can improve the electrochemical parameters of NH₄⁺ EES systems and replace traditional carbon-based anode materials.