Dear Colleagues,

Ever-increasing environmental problems and energy challenges call for the urgent utilization of green, efficient, and sustainable energy production to promote the development of new technologies associated with energy storage and conversion. The past decade has witnessed the rapid and widespread development of metal-based energy conversion and storage technologies, such as Li/Na/K/Zn/Mg/Al metal and metal-air batteries, solar cells, hydrogen production, etc. Meanwhile, with the upsurge in electronic products, smart devices, and electric vehicles, both academic and industrial communities are devoting increasing efforts to designing and manufacturing more advanced energy-related devices, modules, and power source systems with high energy density, high power density, high capacity, long life cycle, and high security. However, the development of advanced power sources relies heavily on advances in material chemistry innovation. Exploring new metallic electrode materials with high performance is highly desirable to satisfy widespread energy storage/conversion applications.

The rapid development of materials science and nanotechnology has led to significant advances in understanding the controllable synthesis, mechanisms, and structure–performance relationships of metallic electrode materials, which have inspired this Research Topic. We cordially invite investigators to contribute original research articles and reviews that will stimulate further research activities in this area and improve our understanding of the key scientific and technological problems in advanced metallic nanomaterials and nanocomposites for energy storage/conversion. In this Special Issue, we welcome articles that focus on describing advanced materials for energy storage devices (Li/Na/K/Zn/Mg/Al metal batteries, metal-air batteries, supercapacitors) and energy conversion (solar cells, fuel cells).

Dr. Yong Liu
Guest Editor

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• metallic nanomaterials and nanocomposites
• metals and alloys
• metal properties
• experimental synthesis
• advanced characterization methods
• energy storage technology
• energy conversion technology

Title: The effect of trace alloying elements on the thermal stability and electrical conductivity of pure copper
Authors: Shijun Liang; Haitao Liu; Kexing Song; Xiaowen Peng; Yanjun Zhou; Huiwen Guo; Liye Niu
Affiliation: School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang, 471023, China Provincial and Ministerial Co-construction of Collaborative Innovation Center for Non-ferrous Metal New Materials and Advanced Processing Technology, Henan Province, Luoyang, 471023, PR China Henan Academy of Sciences, Zhengzhou, 450002, China Chinalco Luoyang Copper Processing Co., Ltd, Luoyang, 471039, China
Abstract: The effects of adding trace transition elements on the grain size thermal stability and electrical conductivity of pure copper were investigated by using optical microscopy (OM), transmission electron microscopy (TEM), and electrical conductivity measurement. The results showed that adding trace Ti and S elements or Cr, Ni, Ag, and S elements can effectively improve the grain size thermal stability of pure copper, while the decrease of the electrical conductivity is small. At room temperature, the average grain sizes of pure copper with trace Ti and S elements and with trace Cr, Ni, Ag, and S elements were 45 μm and 52 μm, respectively, and their electrical conductivities were 101.64% IACS and 100.62% IACS, respectively. After being treated at 900°C/60min, the average grain size of pure copper increased to 231μm, while the average grain size of pure copper with trace Ti and S elements and with Cr, Ni, Ag and S elements were 136μm and 65μm respectively. This is mainly related to the formation of Ti-S phase and Cr-S phase by the interaction of Ti, Cr and S. The Ti-S phase and Cr-S phase can pin the dislocation movement and strengthen the alloy. The precipitation of these phases also reduces the scattering effect of solute atoms on free electrons, thereby reducing the impact of alloy elements on electrical conductivity.

Title: Nickel-Manganese Binary Layered Double Hydroxide nanocatalysts for High-Performance in electrocatalytic decomposition of water
Authors: Shilin Li; Zhi Lu; Kun Tang; Yifan Guo; Guangxin Wang
Affiliation: School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471003, China Henan Engineering Research Center for High Purity Materials and Sputtering Targets, Luoyang 471003, China Luoyang Key Laboratory of High Purity Materials and Sputtering Targets, Henan University of Science and Technology, Luoyang 471003, China
Abstract: Development of efficient electrocatalysts is a key to energy conversion technology. Transition metal layered double hydroxides (LDHs) are expected to replace precious metals in electrolytic water decomposition. In situ growth of NiMn-LDH nanosheets on nickel foam (NF) using a one-step hydrothermal method. The layered double hydroxide (NiMn-LDH/NF) nanocatalysts with different Ni-Mn ratios were prepared. A series of characterization analyses were performed to investigate the effects of ratios on their electrocatalytic properties. When Ni:Mn=3:3 (molar ratio, same below)，the Ni3Mn3-LDH/NF catalyst had a denser nanosheet structure. This structure provided a large layer surface area of LDH, results in enhanced electron transport and ion conduction. Moreover, the dense nanosheets provide more active site exposure, which improves the electrocatalytic activity. The electrochemical performance test shows that the Ni3Mn3-LDH/NF catalyst has an overpotential of 336 mV and a Tafel slope of 89.80 mV/dec at a current density of 10 mA/cm-2. Therefore, the NiMn-LDH/NF nanocatalyst is concluded a promising catalyst for water electrolysis.

Title: Low temperature activation of Sn metal organic complex for advanced lithium storage
Authors: Guilong Liu; Zihan Zhao; Wenzhuo Yuan; Qianru Zhao; Naiteng Wu; Donglei Guo; Weiwei Yuan; Yong Liu; Yehua Su; Xianming Liu
Affiliation: Luoyang Key Laboratory of Green Energy Materials, College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang 471934, P. R. China School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471023, P. R. China Inner Mongolia Shijie Chemical Co., Ltd., Inner Mongolia737300, P. R. China
Abstract: Tin metal organic complex with high specific capacity was considered as a promising anode for Li-ion batteries. However, the low conductivity and large volume expansion usually resulted in its poor cyclic stability. In this work, a low temperature calcination strategy were proposed to improve the lithium storage properties for Sn metal organic complex. The optimized materials exhibited a high specific capacity of 1050 mAh g-1 at 2 A g-1 and 1627 mAh g-1 after 100 cycles at 0.2 A g-1. In addition, ex-situ characterizations proved the electrochemical reconstruction process of low temperature activated Sn metal organic complex. This work proposed a new strategy to prepare electrode materials from metal organic complex.