The volcanic rocks hosting the iron deposits in the Aqishan–Yamansu metallogenic belt are sodium-rich.The geochronology,petrography,and geochemistry of minerals and sodium-rich rocks as well as the relationship betwe...The volcanic rocks hosting the iron deposits in the Aqishan–Yamansu metallogenic belt are sodium-rich.The geochronology,petrography,and geochemistry of minerals and sodium-rich rocks as well as the relationship between these rocks and the iron deposits are studied.Geochemically,the ore-hosting volcanic rocks are sodiumrich(the averages of Na2O and Na2O/K2O are 4.31 wt.%and 8.56,respectively)and belong to the calc-alkaline series.They are enriched in LREEs and LILEs(Ba,U,K,and Sr),but depleted in HFSEs(Nb,Ta,and Ti).SHRIMP zircon U–Pb dating of the crystal tuff in the Aqishan Formation and the dacite in the Tugutu Bulak Formation yields ages of 337.52.3 Ma(n?15,MSWD?0.85)and 313.03.3 Ma(n?13,MSWD?0.74),respectively,indicating that the sodium-rich volcanic rocks formed from the early–late Carboniferous.Electron microprobe data from plagioclases demonstrate that albites and/or oligoclases were formed in the basic–intermediate–acid volcanic rocks.Two stages of albitization are identified,and the latter is likely attributed to the dissolution of iron in the Aqishan–Yamansu belt.The sodium-rich volcanic rocks probably formed by the interaction between volcanic lava and seawater after volcanoes erupted on the seafloor;meanwhile,the albites formed by element substitution in a low-metamorphic environment.The spatiotemporal coupling relationship between sodium-rich volcanic rocks and iron deposits in the Aqishan–Yamansu belt is favorable.Iron dissolved from the dark minerals of basic–intermediate volcanic rocks through sodium metasomatism is one of the material sources for the iron deposits.展开更多
Sodium-ion batteries have attracted significant recent attention currently considering the limited available lithium resource. However, the energy density of sodium-ion batteries is still insufficient compared to lith...Sodium-ion batteries have attracted significant recent attention currently considering the limited available lithium resource. However, the energy density of sodium-ion batteries is still insufficient compared to lithium-ion batteries, mainly because of the unavailability of high-energy cathode materials. In this work, a novel sodium-rich layered oxide material（Na_2 MnO_3） is reported with a dynamical stability similar to that of the Li_2 MnO_3 structure and a high capacity of269.69 mA·h·g1, based on first-principles calculations. Sodium ion de-intercalation and anionic reaction processes are systematically investigated, in association with sodium ions migration phenomenon and structure stability during cycling of Nax MnO3（1 ≤ x ≤ 2）. In addition, the charge compensation during the initial charging process is mainly contributed by oxygen, where the small differences of the energy barriers of the paths 2 c→4 h, 4 h→2 c, 4 h→4 h, 2 c→2 b, and 4 h→2 b indicate the reversible sodium ion occupancy in transitional metal and sodium layers. Moreover, the slow decrease of the elastic constants is a clear indication of the high cycle stability. These results provide a framework to exploit the potential of sodium-rich layered oxide, which may facilitate the development of high-performance electrode materials for sodium-ion batteries.展开更多
Recently, Prussian blue and its analogues （PBAs） have attracted tremendous attention as cathode materials for sodium-ion batteries because of their good cycling performance, low cost, and environmental friendliness....Recently, Prussian blue and its analogues （PBAs） have attracted tremendous attention as cathode materials for sodium-ion batteries because of their good cycling performance, low cost, and environmental friendliness. However, they still suffer from kinetic problems associated with the solid-state diffusion of sodium ions during charge and discharge processes, which leads to low specific capacity and poor rate performances. In this work, novel sodium iron hexacyanoferrate nanospheres with a hierarchical hollow architecture have been fabricated as cathode material for sodium-ion batteries by a facile template method. Due to the unique hollow sphere morpholog~ sodium iron hexacyanoferrate nanospheres can provide large numbers of active sites and high diffusion dynamics for sodium ions, thus delivering a high specific capacity （142 mAh/g）, a superior rate capabili, and an excellent cycling stability. Furthermore, the sodium insertion/extraction mechanism has been studied by in situ X-ray diffraction, which provides further insight into the crystal structure change of the sodium iron hexacyanoferrate nanosphere cathode material during charge and discharge processes.展开更多
基金supported by the National Key R&D Program of China (Nos. 2018YFC0604006, 2017YFC0601204)the National Basic Research Program of China (973 Program, No. 2014CB440803)
文摘The volcanic rocks hosting the iron deposits in the Aqishan–Yamansu metallogenic belt are sodium-rich.The geochronology,petrography,and geochemistry of minerals and sodium-rich rocks as well as the relationship between these rocks and the iron deposits are studied.Geochemically,the ore-hosting volcanic rocks are sodiumrich(the averages of Na2O and Na2O/K2O are 4.31 wt.%and 8.56,respectively)and belong to the calc-alkaline series.They are enriched in LREEs and LILEs(Ba,U,K,and Sr),but depleted in HFSEs(Nb,Ta,and Ti).SHRIMP zircon U–Pb dating of the crystal tuff in the Aqishan Formation and the dacite in the Tugutu Bulak Formation yields ages of 337.52.3 Ma(n?15,MSWD?0.85)and 313.03.3 Ma(n?13,MSWD?0.74),respectively,indicating that the sodium-rich volcanic rocks formed from the early–late Carboniferous.Electron microprobe data from plagioclases demonstrate that albites and/or oligoclases were formed in the basic–intermediate–acid volcanic rocks.Two stages of albitization are identified,and the latter is likely attributed to the dissolution of iron in the Aqishan–Yamansu belt.The sodium-rich volcanic rocks probably formed by the interaction between volcanic lava and seawater after volcanoes erupted on the seafloor;meanwhile,the albites formed by element substitution in a low-metamorphic environment.The spatiotemporal coupling relationship between sodium-rich volcanic rocks and iron deposits in the Aqishan–Yamansu belt is favorable.Iron dissolved from the dark minerals of basic–intermediate volcanic rocks through sodium metasomatism is one of the material sources for the iron deposits.
基金Project suppoted by the National Natural Science Foundation of China(Grant Nos.11774017,51761135129,and 51472010)Beijing Municipal High Level Innovative Team Building Program,China(Grant No.IDHT20170502)
文摘Sodium-ion batteries have attracted significant recent attention currently considering the limited available lithium resource. However, the energy density of sodium-ion batteries is still insufficient compared to lithium-ion batteries, mainly because of the unavailability of high-energy cathode materials. In this work, a novel sodium-rich layered oxide material（Na_2 MnO_3） is reported with a dynamical stability similar to that of the Li_2 MnO_3 structure and a high capacity of269.69 mA·h·g1, based on first-principles calculations. Sodium ion de-intercalation and anionic reaction processes are systematically investigated, in association with sodium ions migration phenomenon and structure stability during cycling of Nax MnO3（1 ≤ x ≤ 2）. In addition, the charge compensation during the initial charging process is mainly contributed by oxygen, where the small differences of the energy barriers of the paths 2 c→4 h, 4 h→2 c, 4 h→4 h, 2 c→2 b, and 4 h→2 b indicate the reversible sodium ion occupancy in transitional metal and sodium layers. Moreover, the slow decrease of the elastic constants is a clear indication of the high cycle stability. These results provide a framework to exploit the potential of sodium-rich layered oxide, which may facilitate the development of high-performance electrode materials for sodium-ion batteries.
文摘Recently, Prussian blue and its analogues （PBAs） have attracted tremendous attention as cathode materials for sodium-ion batteries because of their good cycling performance, low cost, and environmental friendliness. However, they still suffer from kinetic problems associated with the solid-state diffusion of sodium ions during charge and discharge processes, which leads to low specific capacity and poor rate performances. In this work, novel sodium iron hexacyanoferrate nanospheres with a hierarchical hollow architecture have been fabricated as cathode material for sodium-ion batteries by a facile template method. Due to the unique hollow sphere morpholog~ sodium iron hexacyanoferrate nanospheres can provide large numbers of active sites and high diffusion dynamics for sodium ions, thus delivering a high specific capacity （142 mAh/g）, a superior rate capabili, and an excellent cycling stability. Furthermore, the sodium insertion/extraction mechanism has been studied by in situ X-ray diffraction, which provides further insight into the crystal structure change of the sodium iron hexacyanoferrate nanosphere cathode material during charge and discharge processes.
