High specific energy and power sodium-based dual-ion supercabatteries by pseudocapacitive Ni-Zn-Mn ternary perovskite fluorides@reduced graphene oxides anodes with conversion-alloying-intercalation triple mechanisms

Abstract

• A new concept of sodium-based dual-ion supercabattery (S-DICB) was firstly proposed. • The superior pseudocapacitance-dominated kinetics was verified. • The charge storage mechanism of KNZMF@rGO anode was deeply deciphered. • Utilizing different presodiated methods to explore the impact on S-DICB. Sodium (Na)-based electrochemical energy storage devices have drawn particular attention in the renewable and rechargeable energy storage system primarily because of their remarkable energy density and cost-competitive advantages. Herein, we have reported a novel ternary perovskite fluoride K 0.97 Ni 0.31 Zn 0.28 Mn 0.41 F 2.84 with a well-distributed reduced graphene oxide substrate (denoted as KNZMF@rGO) as anode for Na-ion storage that possesses the fast kinetics validated via electrochemical and density functional theory (DFT) methods as well as superior lifespan, which delivers fascinating performances owing to the unexceptionable synergistic effect of Ni, Zn and Mn redox-active species with variable valence. Meanwhile, the surface conversion, alloying and intercalation triple hybridization mechanisms of KNZMF@rGO anode have been explored by the electrochemical analysis and the diverse ex situ physicochemical characterizations. What is more, this work also offers new insights into the device design and proposes the previously unreported “sodium-based dual-ion supercabatteries” (S-DICBs) systems for establishing advanced electrochemical energy storage devices, which exhibit the more intriguing properties than traditional sodium ion capacitors (SICs) and sodium-based dual ion batteries (S-DIBs). In parallel, utilizing different presodiated current densities of anode to explore their impact on the various electrochemical properties of S-DICBs opens up a way for the research of presodiation techniques in the future. A new concept of sodium-based dual-ion supercabattery (S-DICB) was constructed via the pseudocapacitive Ni-Zn-Mn ternary perovskite fluoride (ABF 3 )@reduced graphene oxide (KNZMF@rGO) anode material, which shows the surface conversion/alloying/intercalation triple mechanisms for charge storage. The lower presodiated current density of anode leads to the higher electrochemical properties of S-DICB because of the superior solid electrolyte interface (SEI) film, charge balance and utilization rate of active substance.