Slug Flow Coprecipitation Synthesis of Uniformly-Sized Oxalate Precursor Microparticles for Improved Reproducibility and Tap Density of Li(Ni0.8Co0.1Mn0.1)O2 Cathode Materials.

The microparticle quality and reproducibility of Li(Ni0.8Co0.1Mn0.1)O2 (NCM811) cathode materials are important for Li-ion battery performance but can be challenging to control directly from synthesis. Here, a scalable reproducible synthesis process is designed based on slug flow to rapidly generate uniform micron-size spherical-shape NCM oxalate precursor microparticles at 25-34 °C. The whole process takes only 10 min, from solution mixing to precursor microparticle generation, without needing aging that typically takes hours. These oxalate precursors are convertible to spherical-shape NCM811 oxide microparticles, through a preliminary design of low heating rates (e.g., 0.1 and 0.8 °C/min) for calcination and lithiation. The outcome oxide cathode particles also demonstrate improved tap density (e.g., 2.4 g mL-1 for NCM811) and good specific capacity (202 mAh g-1 at 0.1 C) in coin cells and reasonably good cycling performance with LiF coating.

Effect of Cissus quadrangularis on Fracture Healing in Laboratory Animal / Efeito do Cissus quadrangularis na cicatrização de fraturas em animais de laboratório

Objectives: The present study was designed to examine the efficacy of Cissus quadrangularis paste on fracture healing in artificially induced fractured rabbits. Methods: Fifteen rabbits were separated into three groups namely A, B, and C. Veldt grape paste was applied in groups B and C (Treatment Group) by close reduction and open reduction methods of fracture management; respectively, while group A was kept as control. The blood parameter and fracture healing properties in all animals have been monitored and examined routinely during the study period. Results: Both treated groups revealed lower serum calcium levels (SCL) than the control group after 24 hours of fracture that became within the normal range on the 14th day. Fracture healing in the treated groups has been commenced more rapidly than the control group with complete bridging of discontinuity by a distinct osseous callus in the fracture line on day 7 and complete effacing of fracture line on day 14. Conclusion: We did not find any type of anomalousness, clinical deviations, and alteration of serum calcium level on the 14th day of the fracture in treated animals hence Veldt Grape paste could be readily applicable to the management of the fracture in animals.

Objetivos: avaliar a eficácia da pasta de Cissus quadrangularis na consolidação de fraturas em coelhos fraturados artificialmente. Metodos: quinze coelhos foram separados em três grupos (A, B e C). A pasta foi aplicada nos grupos B e C (Grupo de Tratamento) pelos métodos de redução fechada e redução aberta de gerenciamento de fraturas; respectivamente. O grupo A foi mantido como controle. O parâmetro sanguíneo e as propriedades de cicatrização de fraturas em todos os animais foram monitorados e examinados, rotineiramente, durante o período do estudo. Resultados: ambos os grupos tratados revelaram níveis séricos de cálcio (SCL) mais baixos do que o grupo controle, após 24 horas de fratura que se tornou normal no 14º dia. A cicatrização da fratura nos grupos tratados foi iniciada mais rapidamente do que o grupo controle, com ponte completa de descontinuidade por um calo ósseo distinto na linha de fratura no dia 7 e apagamento completo da linha de fratura no dia 14. Conclusao: não encontramos nenhum tipo de anomalia, desvios clínicos e alteração do nível sérico de cálcio no 14º dia da fratura nos animais tratados, portanto, a pasta Veldt Grape pode ser aplicável ao manejo da fratura em animais.

Scalable Advanced Li(Ni0.8Co0.1Mn0.1)O2 Cathode Materials from a Slug Flow Continuous Process.

Li[Ni0.8Co0.1Mn0.1]O2 (LNCMO811) is the most studied cathode material for next-generation lithium-ion batteries with high energy density. However, available synthesis methods are time-consuming and complex, restricting their mass production. A scalable manufacturing process for producing NCM811 hydroxide precursors is vital for commercialization of the material. In this work, a three-phase slug flow reactor, which has been demonstrated for its ease of scale-up, better synthetic control, and excellent uniform mixing, was developed to control the initial stage of the coprecipitation of NCM811 hydroxide. Furthermore, an equilibrium model was established to predict the yield and composition of the final product. The homogeneous slurry from the slug flow system was obtained and then transferred into a ripening vessel for the necessary ripening process. Finally, the lithium-nickel-cobalt-manganese oxide was obtained through the calcination of the slug flow-derived precursor with lithium hydroxide, having a tap density of 1.3 g cm-3 with a well-layered structure. As-synthesized LNCMO811 shows a high specific capacity of 169.5 mAh g-1 at a current rate of 0.1C and a long cycling stability of 1000 cycling with good capacity retention. This demonstration provides a pathway toward scaling up the cathode synthesis process for large-scale battery applications.

Defect Engineered Ternary Spinel: An Efficient Cathode for an Aqueous Rechargeable Zinc-Ion Battery of Long-Term Cyclability.

The rational defect engineering of Mn-based spinel cathode materials by metal-ion doping and vacancy creation fosters reversible intercalation/deintercalation of charge carriers and boosts the charge storage performance of an aqueous rechargeable zinc-ion battery (ZIB). Herein, we demonstrate the Zn2+ ion storage performance of a defect-engineered ternary spinel cathode based on Zn, Ni, and Mn. The defect engineering of ZnMn2O4 is achieved by Ni2+ doping and creating a cation (Mn3+ and Zn2+) deficiency. The engineered cathode material has cubic spinel structure in contrast to the defect-free ZnMn2O4. The DFT studies show that the defect engineering modifies the electronic structure and improves the electronic conductivity. An aqueous rechargeable ZIB is fabricated by using the spinel cathode, and its performance is evaluated in terms of charge-discharge cycling stability, specific capacity, and so on. The ternary spinel-based ZIB has a very long charge-discharge cycling stability with a specific capacity as high as 265 mAh g-1 (at 100 mA g-1). A 2-fold enhancement in the specific capacity is observed after 5000 cycles. Ni doping affords ultralong cycling stability. The self-discharge studies for a year show that the device retains 63% of the initial performance.

Advanced Oxygen Electrocatalyst for Air-Breathing Electrode in Zn-Air Batteries.

The electrochemical reduction of oxygen to water and the evolution of oxygen from water are two important electrode reactions extensively studied for the development of electrochemical energy conversion and storage technologies based on oxygen electrocatalysis. The development of an inexpensive, highly active, and durable nonprecious-metal-based oxygen electrocatalyst is indispensable for emerging energy technologies, including anion exchange membrane fuel cells, metal-air batteries (MABs), water electrolyzers, etc. The activity of an oxygen electrocatalyst largely decides the overall energy storage performance of these devices. Although the catalytic activities of Pt and Ru/Ir-based catalysts toward an oxygen reduction reaction (ORR) and an oxygen evolution reaction (OER) are known, the high cost and lack of durability limit their extensive use for practical applications. This review article highlights the oxygen electrocatalytic activity of the emerging non-Pt and non-Ru/Ir oxygen electrocatalysts including transition-metal-based random alloys, intermetallics, metal-coordinated nitrogen-doped carbon (M-N-C), and transition metal phosphides, nitrides, etc., for the development of an air-breathing electrode for aqueous primary and secondary zinc-air batteries (ZABs). Rational surface and chemical engineering of these electrocatalysts is required to achieve the desired oxygen electrocatalytic activity. The surface engineering increases the number of active sites, whereas the chemical engineering enhances the intrinsic activity of the catalyst. The encapsulation or integration of the active catalyst with undoped or heteroatom-doped carbon nanostructures affords an enhanced durability to the active catalyst. In many cases, the synergistic effect between the heteroatom-doped carbon matrix and the active catalyst plays an important role in controlling the catalytic activity. The ORR activity of these catalysts is evaluated in terms of onset potential, number of electrons transferred, limiting current density, and durability. The bifunctional oxygen electrocatalytic activity and ZAB performance, on the other hand, are measured in terms of potential gap between the ORR and OER, ΔE = Ej10OER - E1/2ORR, specific capacity, peak power density, open circuit voltage, voltaic efficiency, and charge-discharge cycling stability. The nonprecious metal electrocatalyst-based ZABs are very promising and they deliver high power density, specific capacity, and round-trip efficiency. The active site for oxygen electrocatalysis and challenges associated with carbon support is briefly addressed. Despite the considerable progress made with the emerging electrocatalysts in recent years, several issues are yet to be addressed to achieve the commercial potential of rechargeable ZAB for practical applications.

Aqueous Rechargeable Zn-ion Batteries: Strategies for Improving the Energy Storage Performance.

The growing demand for the renewable energy storage technologies stimulated the quest for efficient energy storage devices. In recent years, the rechargeable aqueous zinc-based battery technologies are emerging as a compelling alternative to the lithium-based batteries owing to safety, eco-friendliness, and cost-effectiveness. Among the zinc-based energy devices, rechargeable zinc-ion batteries (ZIBs) are drawing considerable attention. However, they are plagued with several issues, including cathode dissolution, dendrite formation, etc.. Despite several efforts in the recent past, ZIBs are still in their infant stages and have yet to reach the stage of large-scale production. Finding stable Zn2+ intercalation cathode material with high operating voltage and long cycling stability as well as dendrite-free Zn anode is the main challenge in the development of efficient zinc-ion storage devices. This Review discusses the various strategies, in terms of the engineering of cathode, anode and electrolyte, adopted for improving the charge storage performance of ZIBs and highlights the recent ZIB technological innovations. A brief account on the history of zinc-based devices and various cathode materials tested for ZIB fabrication in the last five years are also included. The main focus of this Review is to provide a detailed account on the rational engineering of the electrodes, electrolytes, and separators for improving the charge storage performance with a future perspective to achieving high energy density and long cycling stability and large-scale production for practical application.

A Self-Healing Metal-Organic Hydrogel for an All-Solid Flexible Supercapacitor.

A zinc containing metal-organic gel (Zn-MOG) with embedded free ions, which exhibits self-healing properties, has been synthesized for application in supercapacitors. The activated carbon-based flexible supercapacitor device with the MOG electrolyte has a broad potential window of 2.1 V, with high retention of specific capacitance compared to the traditional polyvinyl alcohol (PVA)-based gel. The Zn-MOG does not require an additional electrolyte. The sodium and sulphate ions embedded in the MOG are sufficient enough for the charge storage.