Chitosan-reinforced gelatin composite hydrogel as a tough, anti-freezing, and flame-retardant gel polymer electrolyte for flexible supercapacitors.

Hydrogel-based electrolytes for flexible solid-state supercapacitors (SSCs) have received significant attention due to their mechanical robustness and stable electrochemical performance over a wide temperature range. However, achieving flame retardancy in such SSCs at subzero temperatures to increase their practical utility remains challenging. Furthermore, there is a need for sustainable and bio-friendly SSCs that use natural polymer-based hydrogel electrolytes. This study reports a novel approach for developing a chitosan-reinforced anti-freezing ionic conductive gelatin hydrogel to meet these demands. Immersion of chitosan-containing gelatin hydrogels in salt solutions caused chitosan precipitation, resulting in composite hydrogels. The precipitated chitosan contributes to the reinforcement of the gelatin hydrogel network, resulting in a high mechanical toughness of up to 3.81 MJ/m3, a fracture energy of 26 kJ/m2, anti-freezing properties (below -30 °C), and excellent flame retardancy without softening. Furthermore, the hydrogel exhibits excellent electrochemical performance, with an ionic conductivity ranging from 72 mS/cm at room temperature (26 °C) to 39 mS/cm at -30 °C. The proposed hydrogel exhibits potential for use in SSC as a gel polymer electrolyte. This study demonstrates a novel strategy for controlling the mechanical, thermal, and electrochemical characteristics of flexible supercapacitors using biological macromolecules.

Improving the Performance of Aqueous Zinc-ion Batteries by Inhibiting Zinc Dendrite Growth: Recent Progress.

Aqueous zinc-ion batteries (ZIBs) are promising candidates for the next-generation high-energy storage devices, owing to their resource availability, low cost, eco-friendliness, and high safety. The zinc (Zn) metal anode in a suitable battery system, including an electrolyte and a high-performance cathode electrode, can deliver an excellent electrochemical performance. However, several obstacles must be overcome to utilize aqueous ZIBs. Among these, Zn dendrite growth, corrosion, and side reactions severely impair the performance of rechargeable ZIBs. To deal with these issues, a profound understanding of the mechanism of the matter occurring in electrochemical cycles is essential to thoroughly solve the challenges. Instead of focusing solely on techniques for improving the performance of Zn metal anodes, this review delves into and summarizes the causes of side reactions and dendrite formation, thereby establishing a logical system of methodologies for improving the electrochemical performance of mild aqueous ZIBs. The correlation between the Zn metal anode, aqueous electrolyte, separators and the performance of ZIBs is also discussed in detail. There is also a brief perspective on the future development of Zn metal anodes in aqueous solutions. This study sheds a light on the challenges associated with the construction of high-performance ZIBs, which will significantly aid in their practical implementation.

Unraveling the Dynamic Interfacial Behavior of LiCoO2 at Various Voltages with Lithium Bis(oxalato)borate for Lithium-Ion Batteries.

The electrochemical dynamic behavior of the solid electrolyte interface (SEI) formed on LiCoO2 (LCO) by lithium bis(oxalato)borate (LiBOB) is investigated at various cutoff voltages. Particularly, for layered cathode active materials, various cutoff voltages are used to control the delithiation states; however, systematic investigations of the voltage and SEI are lacking. To increase the practical energy density of the LCO, a high cutoff voltage is pursued to utilize a state of high delithiation. However, this high cutoff voltage causes the electrolyte to undergo side reactions and the crystalline structure changes irreversibly, limiting the cycle life. In a low-voltage environment (<4.7 V), LiBOB improves the initial Coulombic efficiency and cycling performance by forming an effective SEI, which suppresses side reactions. At higher voltage levels (4.7-4.9 V), LiBOB no longer effectively protects the surface, causing the electrochemical performance to decrease rapidly. The main cause of this phenomenon is the decomposition of LiBOB-SEI at a high voltage, as shown by systematic surface and electrochemical analyses comprising linear sweep voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy. In conclusion, LiBOB can suppress side reactions of the electrolyte by SEI formation, but the SEI decomposes at voltage levels higher than 4.7 V.

Zn-Based Deep Eutectic Solvent as the Stabilizing Electrolyte for Zn Metal Anode in Rechargeable Aqueous Batteries.

Owing to its low cost and high safety, metallic zinc has received considerable attention as an anode material for zinc aqueous batteries (ZIBs). However, the Zn metal instability as a result ultrafast of obstinate dendrite formation, free-water-induced parasite reactions, and corrosive electrolytes has detrimental effects on the implementation of ZIBs. We present an alternative stable electrolyte for ZIBs based on a zinc chloride/ethylene glycol deep eutectic solvent (DES). This electrolyte consists of abundant low-cost materials and a utilizable Zn2+ concentration of approximately 1 M. It combines the advantages of the aqueous and DES media to provide safe and reversible Zn plating/stripping with a two-fold increase in the cycling life compared to that of conventional aqueous electrolytes. With these advantages, the Zn symmetric cell operates at 0.2 mA cm-2 for 300 h. Due to its high efficiency and compositional versatility, this electrolyte enables the investigation of a non-aqueous electrolyte family for ZIBs that fulfill grid-scale electrical energy storage requirements.

A dataset of the thioacetmide supported formation of ZrO2 coating on Ni-rich layered structure cathode materials in lithium-ion batteries.

A dataset in this report is regarding a research article "Crucial Role of Thioacetamide for ZrO2 Coating on the Fragile Surface of Ni-rich Layered Cathode in Lithium Ion Batteries" [1]. Thioacetamide (TA) is introduced to form a homogeneous ZrO2-coating in a facile method through washing with Zr(SO4)2 aqueous solution. The presence of the data in this paper indicated the role of TA for surface modification of LiNi0.82Co0.09Mn0.09O2 (NCM82) materials by ZrO2, leading to improve the electrochemical performance of NCM82 Ni-rich cathode materials. These data were proceeded measurement electrochemical properties of cathode electrode on a battery cycler, the surface characteristics of the cathode materials were investigated by SEM, EDS mapping, TEM and XPS. X-ray diffraction (XRD, Rigaku, SmartLab) was used to evaluate the influence of the coating layer on the microstructure of active materials.