다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Because of the remarkably high theoretical energy output, metal–air batteries represent one class of promising power sources for applications in next-generation electronics, electrified transportation and energy storage of smart grids. The most prominent feature of a metal–air battery is the combination of a metal anode with high energy density and an air electrode with open structure to draw cathode active materials (i.e., oxygen) from air. In this critical review, we present the fundamentals and recent advances related to the fields of metal–air batteries, with a focus on the electrochemistry and materials chemistry of air electrodes. The battery electrochemistry and catalytic mechanism of oxygen reduction reactions are discussed on the basis of aqueous and organic electrolytes. Four groups of extensively studied catalysts for the cathode oxygen reduction/evolution are selectively surveyed from materials chemistry to electrode properties and battery application: Pt and Pt-based alloys (e.g., PtAu nanoparticles), carbonaceous materials (e.g., graphene nanosheets), transition-metal oxides (e.g., Mn-based spinels and perovskites), and inorganic–organic composites (e.g., metal macrocycle derivatives). The design and optimization of air-electrode structure are also outlined. Furthermore, remarks on the challenges and perspectives of research directions are proposed for further development of metal–air batteries (219 references).

Metal–air batteries: from oxygen reduction electrochemistry to cathode catalysts

Liming Dai,*,†,‡ Yuhua Xue,†,‡ Liangti Qu,* Hyun-Jung Choi, and Jong-Beom Baek* †Center of Advanced Science and Engineering for Carbon (Case4Carbon), Department of Macromolecular Science and Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States Key Laboratory of Cluster Science, Ministry of Education of China, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Department of Chemistry, School of Science, Beijing Institute of Technology, Beijing 100081, People’s Republic of China School of Energy and Chemical Engineering/Center for Dimension-Controllable Covalent Organic Frameworks, Ulsan National Institute of Science and Technology (UNIST), 100 Banyeon, Ulsan, 689-798, South Korea

Metal-free catalysts for oxygen reduction reaction.

Review on recent progress of nanostructured anode materials for Li-ion batteries

We developed two-step solution-phase reactions to form hybrid materials of Mn3O4 nanoparticles on reduced graphene oxide (RGO) sheets for lithium ion battery applications. Mn3O4 nanoparticles grown selectively on RGO sheets over free particle growth in solution allowed for the electrically insulating Mn3O4 nanoparticles wired up to a current collector through the underlying conducting graphene network. The Mn3O4 nanoparticles formed on RGO show a high specific capacity up to ~900mAh/g near its theoretical capacity with good rate capability and cycling stability, owing to the intimate interactions between the graphene substrates and the Mn3O4 nanoparticles grown atop. The Mn3O4/RGO hybrid could be a promising candidate material for high-capacity, low-cost, and environmentally friendly anode for lithium ion batteries. Our growth-on-graphene approach should offer a new technique for design and synthesis of battery electrodes based on highly insulating materials.

Mn3O4-Graphene Hybrid as a High Capacity Anode Material for Lithium Ion Batteries

Olivine-structured LiFePO4 has been the focus of research in developing low cost, high performance cathode materials for lithium ion batteries. Various processes have been developed to synthesize LiFePO4 or C/LiFePO4 (carbon coating on LiFePO4), and some of them are being used to mass produce C/LiFePO4 at the commercial or pilot scale. Due to the low intrinsic electronic and ionic conductivities of LiFePO4, the decrease of particle size and the nano-layer of carbon coating on LiFePO4 particle surfaces are necessary to achieve a high electrochemical performance. Significant progress has been made in understanding and controlling phase purity, particle size and carbon coating of the C/LiFePO4 composite material in the past. However, there are still many challenges in achieving a high quality product with high consistency. In this review, we summarize some of the recent progress and advances based on selected reports from peer-reviewed journal publications. Several typical synthesis methods and the effect of carbon coating quality on the properties of C/LiFePO4 composite are reviewed. An insight into the future research and further development of C/LiFePO4 composite is also discussed.

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Understanding and recent development of carbon coating on LiFePO4 cathode materials for lithium-ion batteries

Rechargeable batteries can effectively store electrical energy as chemical energy, and release it when needed, providing a good choice for applications in electric vehicles (EVs). Naturally, safety concerns are the key issue for the application of battery technology in EVs. Olivine LiFePO4 is considered to be the most promising cathode material for lithium-ion batteries due to its environmental friendliness, high cycling performance and safety characteristics. Some important breakthroughs in recent years have allowed its successful commercialization. However, in spite of its success, the commercial application of LiFePO4 batteries in EVs is still hindered by some technological obstacles. Herein, we provide an update on our previous review, and overview the most significant advances in the remaining challenges for this promising battery material. New research directions and future trends have also been discussed.

Jiajun Wang

Papers

Understanding and recent development of carbon coating on LiFePO4 cathode materials for lithium-ion batteries

Olivine LiFePO4: the remaining challenges for future energy storage

Effect of carbon black support corrosion on the durability of Pt/C catalyst

Challenges and opportunities of nanostructured materials for aprotic rechargeable lithium–air batteries

Superior energy capacity of graphene nanosheets for a nonaqueous lithium-oxygen battery