Novel guar‐gum electrolyte to aggrandize the performance of LaMnO 3 perovskite‐based zinc‐air batteries

Electronic Booster PEDOT:PSS-Enriched Guar Gum as Eco-Friendly Gel Electrolyte for Supercapacitor

Supercapacitors based on biobased materials have been regarded as alternative portable energy storage technology for wearable or flexible electronics. Herein, we construct a unique electronic booster-imbedded biopolymer electrolyte with enhanced power density and long cycling life quasi-solid-state supercapacitor using poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) PEDOT:PSS/guar gum (GG). The eco-friendly 2% (v/v) PEDOT:PSS in the GG matrix doped with 0.05 wt % of lithium perchlorate (LiClO4) was highly flexible and showed an ionic conductivity of 10-2 S cm-1 at 323 K. The surface morphology showed unique potential wells of PEDOT:PSS boosting the nonconductive GG and interaction with activated carbon-based electrodes. As a result, a specific capacitance of 141 F g-1 at 5 mV s-1 was observed. The cyclic stability was 98% even after 1000 charge-discharge study cycles. To the best of our knowledge, this is the first work demonstrating a high-performance supercapacitor with conducting polymer-boosted guar gum as the polymer gel electrolyte, and it provides scope for understanding further stability testing and the interaction mechanism within the polymer matrix.

Strategic Design and Insights into Lanthanum and Strontium Perovskite Oxides for Oxygen Reduction and Oxygen Evolution Reactions

Perovskite oxides exhibit bifunctional activity for both oxygen reduction (ORR) and oxygen evolution reactions (OER), making them prime candidates for energy conversion in applications like fuel cells and metal-air batteries. Their intrinsic catalytic prowess, combined with low-cost, abundance, and diversity, positions them as compelling alternatives to noble metal and metal oxides catalysts. This review encapsulates the nuances of perovskite oxide structures and synthesis techniques, providing insight into pivotal active sites that underscore their bifunctional behavior. The focus centers on the breakthroughs surrounding lanthanum (La) and strontium (Sr)-based perovskite oxides, specifically their roles in zinc-air batteries (ZABs). An introduction to the mechanisms of ORR and OER is provided. Moreover, the light is shed on strategies and determinants central to optimizing the bifunctional performance of La and Sr-based perovskite oxides.

Research Progress of Perovskite-Based Bifunctional Oxygen Electrocatalyst in Alkaline Conditions

In light of the depletion of conventional energy sources, it is imperative to conduct research and development on sustainable alternative energy sources. Currently, electrochemical energy storage and conversion technologies such as fuel cells and metal-air batteries rely heavily on precious metal catalysts like Pt/C and IrO2, which hinders their sustainable commercial development. Therefore, researchers have devoted significant attention to non-precious metal-based catalysts that exhibit high efficiency, low cost, and environmental friendliness. Among them, perovskite oxides possess low-cost and abundant reserves, as well as flexible oxidation valence states and a multi-defect surface. Due to their advantageous structural characteristics and easily adjustable physicochemical properties, extensive research has been conducted on perovskite-based oxides. However, these materials also exhibit drawbacks such as poor intrinsic activity, limited specific surface area, and relatively low apparent catalytic activity compared to precious metal catalysts. To address these limitations, current research is focused on enhancing the physicochemical properties of perovskite-based oxides. The catalytic activity and stability of perovskite-based oxides in Oxygen Reduction Reaction/Oxygen Evolution Reaction (ORR/OER) can be enhanced using crystallographic structure tuning, cationic regulation, anionic regulation, and nano-processing. Furthermore, extensive research has been conducted on the composite processing of perovskite oxides with other materials, which has demonstrated enhanced catalytic performance. Based on these different ORR/OER modification strategies, the future challenges of perovskite-based bifunctional oxygen electrocatalysts are discussed alongside their development prospects.

High energy storage capabilities of CaCu3Ti4O12 for paper-based zinc-air battery

Zinc–air batteries proffer high energy density and cyclic stability at low costs but lack disadvantages like sluggish reactions at the cathode and the formation of by-products at the cathode. To resolve these issues, a new perovskite material, CaCu₃Ti₄O₁₂ (CCTO), is proposed as an efficacious electrocatalyst for oxygen evolution/reduction reactions to develop zinc–air batteries (ZAB). Synthesis of this material adopted an effective oxalate route, which led to the purity in the electrocatalyst composition. The CCTO material is a proven potential candidate for energy applications because of its high dielectric permittivity (ε) and occupies an improved ORR-OER activity with better onset potential, current density, and stability. The Tafel value for CCTO was obtained out to be 80 mV dec⁻¹. The CCTO perovskite was also evaluated for the zinc–air battery as an air electrode, corresponding to the high specific capacitance of 801 mAh g⁻¹ with the greater cyclic efficiency and minimum variations in both charge/discharge processes. The highest power density (P_max) measured was 127 mW cm⁻². Also, the CCTO based paper battery shows an excellent performance achieving a specific capacity of 614 mAh g⁻¹. The obtained results promise CCTO as a potential and cheap electrocatalyst for energy applications.