Chemical Reaction Controlled Synthesis Of Copper Compounds And Their Materials Performances

Both physical and chemical properties of inorganic materials can be controlled by their structures, morphologies, and synthesis methods, which can further affect their performances in the field of catalysis, sensing, and electrochemical energy storage. With the rapid progress in inorganic chemistry, the synthesis of inorganic materials with controllable morphologies, structures and properties has achieved big success. However, how chemical reactions control the structure and property of materials, and how the crystallization process affects the performance of materials are still a lack of in-depth understanding. This PhD dissertation focuses on the chemical reaction-controlled crystallization of copper compounds by designing various vapor-, liquid-and solid-phase reactions; in addition, by systematically studing the electrochemical performances of the as-synthesized materials, this dissertation systematically reveals the relationship of chemical reaction-crystallization and crystallization-electrochemical properties.A vapor-phase chemical reaction controlled crystallization route to tri-component copper compounds has been designed. Firstly, by controlling the oxidation sequence of Cu current collector, Cuâ†'Cu2Oâ†'CuO, CuxO-Cu integrated electrode is obtained, which can show better cycling stability and higher capability than those CuxO-C blend electrodes. Secondly, filter paper burning route is designed to fast synthesize CuO/Cu2O/Cu electrode materials. This burning method can show advantages as self-redoxable, self-heating and ultrafast synthesis route. When served as lithium ion battery anodes, these CuO/Cu2O/Cu nanomaterial electrodes can display high cycling stability with96%retention of reversible capacity after60discharge-charge cycles.By adjusting the equilibrium between complexation, precipitation and redox reactions in liquid-phase reaction and crystallization kinetics, Cu2O micro/nanocrystals with differetn morphologies can be synthesized, i.e., hopper cube, cube, octahedron, rhombic dodecahedra, truncated octahedron, hollow octahedron etc. By designing ligand chemical reaction systems, hopper cubes with tunnel structures were crystallized. Based on hard and soft acid-base theory, a chemoaffinity-mediated crystallization strategy has been presented to fabricate Cu2O micro/nanocrystals by utilizing the different chemical affinities between lewis base of OH-, SO42-, NO3-, Ac-and Cl-and lewis acid of Cu2+. The pH-controlled precursor formation-crystallization route has been designed to crystallize Cu2O with systematic shape evolution. These liquid-phase chemical reaction controlled synthesis method can provide a novel synthesis route for the crystallization of metal and metal oxide materials with controllable morphologies. Low temperature and in-situ electrochemical reaction routes have been designed for the syntehsis of high-performance copper compound electrode materials. Various CuO crystallized morphologies i.e., nanoribbons, nanowires, nanosheets and nanoparticles aggregation have been crystallized by designing mechanochemical reactions route, room-temperature chemical transformation route and in-situ electrochemical reaction route. By controlling in-situ solid-phase chemical and electrochemical reactions, single-crystal CuO sheets were transformed into nanoparticles aggregation in CuO-Cu integrated anodes, leading to the production of many electroactive sites and the enhancement of electrochemical performance. After110cycles, the discharge capacity of CuO-Cu integrated anode retains a large value of706mAh g-1which is beyond the theoretical capacity of CuO materials (674mAh g-1). The higher capacity and good cycling characteristics of CuO-Cu integrated anode can be attributed to the oxidation of Cu current collector and the structure stability of nanoparticle aggregations.