Mechanochemically-assisted synthesis of 3D, 2D and quasi 2D lead halide perovskites for supercapacitor applications

Abstract

Lead halide perovskite (LHP) thin-film-based energy storage devices have gained considerable attention due to their favourable electronic and ionic conductivity. Here, we have fabricated electrodes for electrolyte-based supercapacitors using mechanochemically synthesized LHPs and demonstrated that the type of starting material and dimensionality of the perovskite strongly influence the device performance. First, we have compared the electrochemical performance of electrodes obtained from the single crystalline (SCP) and mechanosynthesized (MSP) methylammonium lead tribromide (MAPbBr₃), and ∼2 times improvement was observed in the MAPbBr₃ MSP-based energy storage device due to higher average microstrain induced by ball milling, which modulates ion migration. Next, we fabricated electrodes based on mechanochemically synthesized MAPbBr₃, 2D MA₂PbBr₄ and quasi-2D BA₂MAPb₂Br₇, and demonstrated that the structure and ion migration could play a vital role in the overall performance of the LHP-based electrochemical supercapacitor. The areal capacitance (∼209 mF cm⁻²) and specific capacitance (∼138.35 F g⁻¹) calculated at a scan rate of 5 mV s⁻¹ with the maximum power density and cycle stability were found to be highest in the 2D MA₂PbBr₄ perovskite-based supercapacitor. This result can be attributed to its smallest particle size, which helps to improve the interaction between electrolyte ions and the perovskite electrode interface at a lower scan rate.