Probing the electrochemical properties of biopolymer modified EMD nanoflakes through electrodeposition for high performance alkaline batteries

Gold Nanomaterials-Based Electrochemical Sensors and Biosensors for Phenolic Antioxidants Detection: Recent Advances

Antioxidants play a central role in the development and production of food, cosmetics, and pharmaceuticals, to reduce oxidative processes in the human body. Among them, phenolic antioxidants are considered even more efficient than other antioxidants. They are divided into natural and synthetic. The natural antioxidants are generally found in plants and their synthetic counterparts are generally added as preventing agents of lipid oxidation during the processing and storage of fats, oils, and lipid-containing foods: All of them can exhibit different effects on human health, which are not always beneficial. Because of their relevant bioactivity and importance in several sectors, such as agro-food, pharmaceutical, and cosmetic, it is crucial to have fast and reliable analysis Rmethods available. In this review, different examples of gold nanomaterial-based electrochemical (bio)sensors used for the rapid and selective detection of phenolic compounds are analyzed and discussed, evidencing the important role of gold nanomaterials, and including systems with or without specific recognition elements, such as biomolecules, enzymes, etc. Moreover, a selection of gold nanomaterials involved in the designing of this kind of (bio)sensor is reported and critically analyzed. Finally, advantages, limitations, and potentialities for practical applications of gold nanomaterial-based electrochemical (bio)sensors for detecting phenolic antioxidants are discussed.

Rational Design of Effective Binders for LiFePO4 Cathodes

Polymer binders are critical auxiliary additives to Li-ion batteries that provide adhesion and cohesion for electrodes to maintain conductive networks upon charge/discharge processes. Therefore, polymer binders become interconnected electrode structures affecting electrochemical performances, especially in LiFePO4 cathodes with one-dimensional Li+ channels. In this paper, recent improvements in the polymer binders used in the LiFePO4 cathodes of Li-ion batteries are reviewed in terms of structural design, synthetic methods, and working mechanisms. The polymer binders were classified into three types depending on their effects on the performances of LiFePO4 cathodes. The first consisted of PVDF and related composites, and the second relied on waterborne and conductive binders. Profound insights into the ability of binder structures to enhance cathode performance were discovered. Overcoming the bottleneck shortage originating from olivine structure LiFePO4 using efficient polymer structures is discussed. We forecast design principles for the polymer binders used in the high-performance LiFePO4 cathodes of Li-ion batteries. Finally, perspectives on the application of future binder designs for electrodes with poor conductivity are presented to provide possible design directions for chemical structures.

A Review of the Use of GPEs in Zinc-Based Batteries. A Step Closer to Wearable Electronic Gadgets and Smart Textiles

With the flourish of flexible and wearable electronics gadgets, the need for flexible power sources has become essential. The growth of this increasingly diverse range of devices boosted the necessity to develop materials for such flexible power sources such as secondary batteries, fuel cells, supercapacitors, sensors, dye-sensitized solar cells, etc. In that context, comprehensives studies on flexible conversion and energy storage devices have been released for other technologies such Li-ion standing out the importance of the research done lately in GPEs (gel polymer electrolytes) for energy conversion and storage. However, flexible zinc batteries have not received the attention they deserve within the flexible batteries field, which are destined to be one of the high rank players in the wearable devices future market. This review presents an extensive overview of the most notable or prominent gel polymeric materials, including biobased polymers, and zinc chemistries as well as its practical or functional implementation in flexible wearable devices. The ultimate aim is to highlight zinc-based batteries as power sources to fill a segment of the world flexible batteries future market.

Energy-saving electrolytic γ-MnO2 generation: non-noble metal electrocatalyst gas diffusion electrode as cathode in acid solution

γ-MnO₂, which is commercially used as an electrode material in batteries, is produced using large amounts of energy and leads to the production of high pollution as a secondary product. Ideally, this material should be fabricated by energy efficient, non-polluting methods at a reasonable cost. This study reports the green fabrication of γ-MnO₂ into a gas diffusion electrode with Pt-free catalysts in acid solution. Cobalt oxide nanoparticles were deposited on few-layer graphene sheets produced via a simple sintering and ultrasonic mixing method, leading to the fabrication of cobalt oxide/few-layer graphene. Co₃O₄ nanoparticles are irregularly shaped and uniformly distributed on the surface of the few-layer graphene sheets. Characterization was conducted by X-ray diffraction, X-ray photoelectron spectroscopy, and field emission scanning electron microscopy. Electrochemical characterization revealed the performance of cobalt oxide/few-layer graphene gas diffusion electrode in an electrolyte of 120 g L⁻¹ manganese sulfate + 30 g L⁻¹ sulfuric acid at 100 A m⁻² at 80 °C. The cobalt oxide/few-layer graphene gas diffusion electrode exhibited a lower cell voltage of 0.9 V and higher electric energy savings of approximately 50% compared with traditional cathodes (copper and carbon).

Co₃O₄/FLG was used as a nanocatalyst to catalyze the ORR in the electrodeposition of MnO₂. The proposed Co₃O₄/FLG nanocomposite GDE exhibited a high activity of 0.9 V at a current density of 100 A m⁻².

Preparation and properties of Pb/Sn/Al laminated composite anode for zinc electrowinning

The use of Pb/Sn/Al composite anode materials has been limited due to the thermodynamic immiscibility between Pb and Al sheets during the welding process. Thus, herein, Sn has been added between Pb and Al sheets to fabricate a Pb/Sn/Al laminated composite via vacuum hot-pressing welding (at a temperature of 230 °C for 12 h under 0.5 MPa). Furthermore, the interfacial microstructure and mechanical and electrical properties are investigated. Good metallurgical bonding has been realized due to the addition of Sn, and block α-Pb and a small amount of β-Sn solid solutions are also formed at the interface. In comparison with the Pb–Ag alloy anode, the Pb/Sn/Al laminated composite presents superior mechanical strength (73.9 MPa), and good electrical conductivity of the Pb/Sn/Al composite has been obtained due to its sandwich laminated structure. Moreover, the Pb/Sn/Al composite reduces the electrode reaction energy and improves the electrocatalytic activity of the electrode to reduce the bath voltage.

The use of Pb/Sn/Al composite anode materials has been limited due to the thermodynamic immiscibility between Pb and Al sheets during the welding process.