Synthesis and electrochemical studies of NaCoPO4 as an efficient cathode material using natural deep eutectic solvents for aqueous rechargeable sodium-ion batteries

In this work, sodium cobalt phosphate (NaCoPO4) was successfully prepared by a cost-effective ionothermal method using a deep eutectic solvent (DES) for the first time. The synthesized NaCoPO4 was used to fabricate a cathode material for aqueous rechargeable sodium-ion batteries. The surface morphology of the prepared materials and its compositional analysis were done by using field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray (EDX) analysis, respectively. The X-ray diffraction (XRD), SEM, and EDX studies revealed that the material has orthorhombic-shaped particle morphology with uniform distribution and is in nanoscale (approximately 50 nm). The nature of the cation inserted (Na+ ion insertion) was confirmed by recording CV profiles at different concentrations of the Na2SO4 electrolyte. The reversibility of the electrode redox reaction was studied by varying the scan rate in CV studies, and it was found that the electrode exhibits a reversible behavior with a resistive behavior. In GCPL studies, the cell TiO2/2MNa2SO4/NaCoPO4 showed significant reversibility with a prominent discharge capacity of 85 mAh g-1 at 0.1°C and 88% of capacity retention after 100 cycles. Thus, the prepared materials could be used as an effective futuristic alternative battery material for rechargeable batteries.

Fully-Printed Flexible Aqueous Rechargeable Sodium-Ion Batteries

The flexible aqueous rechargeable sodium-ion batteries (ARSIBs) are a promising portable energy storage system that can meet the flexibility and safety requirements of wearable electronic devices. However, it faces huge challenges in mechanical stability and facile manufacturing processes. Herein, the first fully-printed flexible ARSIBs with appealing mechanical performance by screen-printing technique is prepared, which utilizes Na3V2(PO4)2F3/C (NVPF/C) as the cathode and 2% nitrogenous carbon-loaded Na3MnTi(PO4)3/C (NMTP/C/NC) as the anode. In particular, the organic co-solvent ethylene glycol (EG) is cleverly added to 17 m (mol kg-1) NaClO4 electrolyte to prepare a 17 m NaClO4-EG mixed electrolyte. This mixed electrolyte can withstand low temperatures of -20 °C in practical applications. Encouragingly, the fully-printed flexible ARSIBs (NMTP/C/NC//NVPF/C) exhibit a discharge capacity of 40.1 mAh g-1, an energy density of 40.1 Wh kg-1, and outstanding cycle performance. Moreover, these batteries with various shapes can be used as an energy wristband for an electronic watch in the bending states. The fully-printed flexible ARSIBs in this work are expected to shed light on the development of energy for wearable electronics.

A Comprehensive Evaluation of Battery Technologies for High-Energy Aqueous Batteries

Aqueous batteries have garnered significant attention in recent years as a viable alternative to lithium-ion batteries for energy storage, owing to their inherent safety, cost-effectiveness, and environmental sustainability. This study offers a comprehensive review of recent advancements, persistent challenges, and the prospects of aqueous batteries, with a primary focus on energy density compensation of various battery engineering technologies. Additionally, cutting-edge high-energy aqueous battery designs are emphasized as a reference for future endeavors in the pursuit of high-energy storage solutions. Finally, a dual-compatibility battery configuration perspective aimed at concurrently optimizing cycle stability, redox potential, capacity utilization for both anode and cathode materials, as well as the selection of potential electrode candidates, is proposed with the ultimate goal of achieving cell-level energy densities exceeding 400 Wh kg-1 .

Completely suppressed high-voltage phase transition of P2/O3-Na0.7Li0.1Ni0.1Fe0.2Mn0.6O2via Li/Ni co-doping for sodium storage

A novel P2/O3-Na0.7Li0.1Ni0.1Fe0.2Mn0.6O2 cathode is prepared via Li/Ni co-doping, and delivers attractive cycling and rate performances due to the high Na+ diffusion coefficient and the complete suppression of the high-voltage P2–Z phase transition.

Improved electrode kinetics of a modified Na3V2(PO4)3 cathode through Zr substitution and nitrogen-doped carbon coating towards robust electrochemical performance at low temperature

The substitution of V with Zr in a NASICON structure and an NC coating endow 0.1Zr-NVP/NC with excellent electrochemical performance at low temperature.