(Digital Presentation) Mn-VOH Micro Flakes Interconnected with CNT As Cathodes for Aqueous Zinc-Ion Batteries

With increasing energy consumption and environmental awareness, the demand for next-generation energy storage systems has grown. Aqueous zinc-ion batteries (AZIBs) have received considerable attention among various types of energy storage devices due to their high safety standards and low cost. Herein, we present a sustainable synthesis approach for synthesizing MnVOH@CNT composite material and its application as the cathode material for aqueous Zinc-ion batteries (AZIBs) by using a low-temperature (120 °C) hydrothermal process. Moreover, with a continuous network structure and expanded interlayer spacing, such a configuration can provide rapid electron transfer kinetics (DZn 2+: 10 ̶ 11−10−12 cm2 s−1) while ensuring close interaction between MnVOH and CNT during cycling. The materials have excellent electrochemical properties as cathodes in the AZIBs. The resultant batteries exhibit a high intercalation storage capacity of c.a. 380 mAh g−1 at acurrent density of 0.1 A g−1, minimized polarization, and excellent capacity retention of c.a. 90% after 300 cycles. Furthermore, operando synchrotron X-ray absorption, near-edge spectroscopy was used for the first time to confirm the Zn2+ charge-storage mechanism. Operando synchrotron X-ray diffraction, studies were also done to better understand the structural changes of the MnVOH@CNT nanocomposite during the discharge/charge processes. Meanwhile, the ZIBs using MnVOH@CNT as cathode can maintain an energy density of c.a. 190 Wh kg−1 at a high power density of 3.2 kW kg−1, demonstrating that MnVOH@CNT is a promising cathode material for high-performance cathode material for low-cost and environment-friendly AZIB applications. KEYWORDS: AZIB, MnVOH@CNT, operando XANES, operando XRD, cathode material