Na_(3)V_(2)(PO_(4))_(3)(NVP)has garnered great attentions as a prospective cathode material for sodium-ion batteries(SIBs)by virtue of its decent theoretical capacity,superior ion conductivity and high structural stab...Na_(3)V_(2)(PO_(4))_(3)(NVP)has garnered great attentions as a prospective cathode material for sodium-ion batteries(SIBs)by virtue of its decent theoretical capacity,superior ion conductivity and high structural stability.However,the inherently poor electronic conductivity and sluggish sodium-ion diffusion kinetics of NVP material give rise to inferior rate performance and unsatisfactory energy density,which strictly confine its further application in SIBs.Thus,it is of significance to boost the sodium storage performance of NVP cathode material.Up to now,many methods have been developed to optimize the electrochemical performance of NVP cathode material.In this review,the latest advances in optimization strategies for improving the electrochemical performance of NVP cathode material are well summarized and discussed,including carbon coating or modification,foreign-ion doping or substitution and nanostructure and morphology design.The foreign-ion doping or substitution is highlighted,involving Na,V,and PO_(4)^(3−)sites,which include single-site doping,multiple-site doping,single-ion doping,multiple-ion doping and so on.Furthermore,the challenges and prospects of high-performance NVP cathode material are also put forward.It is believed that this review can provide a useful reference for designing and developing high-performance NVP cathode material toward the large-scale application in SIBs.展开更多
LiNiCoAlO（NCA） with Zr（OH）coating is demonstrated as high performance cathode material for lithium ion batteries（LIBs）. The coated materials are synthesized via a simple dry coating method of NCA with Zr（OH）po...LiNiCoAlO（NCA） with Zr（OH）coating is demonstrated as high performance cathode material for lithium ion batteries（LIBs）. The coated materials are synthesized via a simple dry coating method of NCA with Zr（OH）powders, and then characterized with scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and X-ray photoelectron spectroscopy（XPS）. Experimental results show that amorphous Zr（OH）powders have been successfully coated on the surface of spherical NCA particles, exhibiting improved electrochemical performance. 0.50 wt% Zr（OH）coated NCA delivers a capacity of 197.6 mAh/g at the first cycle and 154.3 mAh/g after 100 cycles with a capacity retention of 78.1% at 1 C rate. In comparison, the pure NCA shows a capacity of 194.6 mAh/g at the first cycle and 142.5 mAh/g after 100 cycles with a capacity retention of 73.2% at 1 C rate. Electrochemical impedance spectroscopy（EIS） results show that the coated material exhibits a lower resistance, indicating that the coating layer can efficiently suppress transition metals dissolution and decrease the side reactions at the surface between the electrode and electrolyte. Therefore, surface coating with amorphous Zr（OH）is a simple and useful method to enhance the electrochemical performance of NCA-based materials for the cathode of LIBs.展开更多
In this paper,we report on the preparation of Li2FeSiO4,sintered Li2FeSiO4,and Li2FeSiO4-C composite with spindle-like morphologies and their application as cathode materials of lithium-ion batteries.Spindle-like Li2F...In this paper,we report on the preparation of Li2FeSiO4,sintered Li2FeSiO4,and Li2FeSiO4-C composite with spindle-like morphologies and their application as cathode materials of lithium-ion batteries.Spindle-like Li2FeSi04 was synthesized by a facile hydrothermal method with（NH4）2Fe（SO4）2 as the iron source.The spindle-like Li2FeSiO4 was sintered at 600 ℃ for 6 h in Ar atmosphere.Li2FeSiO4-C composite was obtained by the hydrothermal treatment of spindle-like Li2FeSiO4 in glucose solution at 190 ℃ for 3 h.Electrochemical measurements show that after carbon coating,the electrode performances such as discharge capacity and high-rate capability are greatly enhanced.In particular.Li2FeSiO4-C with carbon content of 7.21 wt%delivers the discharge capacities of 160.9 mAh·g-1 at room temperature and 213 mAh·g-1 at45℃（0.1 C）,revealing the potential application in lithium-ion batteries.展开更多
B4C, SiC and C, Cu functionally graded-materials (FGMs) have been developed by plasma spraying and hot pressing. Their high-heat flux properties have been investigated by high energy laser and electron beam for the si...B4C, SiC and C, Cu functionally graded-materials (FGMs) have been developed by plasma spraying and hot pressing. Their high-heat flux properties have been investigated by high energy laser and electron beam for the simulation of plasma disruption process of the future fusion reactors, And a study on eroded products of B4C/Cu FGM under transient thermal load of electron beam was performed. In the experiment, SEM and EDS analysis indicated that B4C and SiC were decomposed, carbon was preferentially evaporated under high thermal load, and a part of Si and Cu were melted, in addition, the splash of melted metal and the particle emission of brittle destruction were also found. Different erosive behaviors of carbon-based materials (CBMs) caused by laser and electron beam were also discussed.展开更多
High-density Cu2ZnSnS4 （CZTS） materials are prepared via the mechanical alloying and high pressure sintering method using Cu2S, ZnS and SnS2 as the raw materials. The morphological, structural, compositional and ele...High-density Cu2ZnSnS4 （CZTS） materials are prepared via the mechanical alloying and high pressure sintering method using Cu2S, ZnS and SnS2 as the raw materials. The morphological, structural, compositional and electrical properties of the materials are investigated by using x-ray diffraction, scanning electron microscopy, and energy dispersive x-ray spectroscopy, as well as by the Raman scattering and the Hall EFfect measurements. The CZTS synthesized under 5 GPa and 800℃ shows a p-type conductivity, with a resistivity of 9.69 × 10^-2 Ω.cm and a carrier concentration of 1.45 × 10^20 cm-3. It is contributed to by the large grains in the materials reducing the grain boundaries, thus effectively reducing the recombination of the charge carriers.展开更多
基金partly supported by the National Natural Science Foundation of China(Grant No.52272225).
文摘Na_(3)V_(2)(PO_(4))_(3)(NVP)has garnered great attentions as a prospective cathode material for sodium-ion batteries(SIBs)by virtue of its decent theoretical capacity,superior ion conductivity and high structural stability.However,the inherently poor electronic conductivity and sluggish sodium-ion diffusion kinetics of NVP material give rise to inferior rate performance and unsatisfactory energy density,which strictly confine its further application in SIBs.Thus,it is of significance to boost the sodium storage performance of NVP cathode material.Up to now,many methods have been developed to optimize the electrochemical performance of NVP cathode material.In this review,the latest advances in optimization strategies for improving the electrochemical performance of NVP cathode material are well summarized and discussed,including carbon coating or modification,foreign-ion doping or substitution and nanostructure and morphology design.The foreign-ion doping or substitution is highlighted,involving Na,V,and PO_(4)^(3−)sites,which include single-site doping,multiple-site doping,single-ion doping,multiple-ion doping and so on.Furthermore,the challenges and prospects of high-performance NVP cathode material are also put forward.It is believed that this review can provide a useful reference for designing and developing high-performance NVP cathode material toward the large-scale application in SIBs.
基金supported by the National Projects of NSFC(21322101 and 21231005)MOE(B12015 and IRT13R30)
文摘LiNiCoAlO（NCA） with Zr（OH）coating is demonstrated as high performance cathode material for lithium ion batteries（LIBs）. The coated materials are synthesized via a simple dry coating method of NCA with Zr（OH）powders, and then characterized with scanning electron microscopy（SEM）, transmission electron microscopy（TEM） and X-ray photoelectron spectroscopy（XPS）. Experimental results show that amorphous Zr（OH）powders have been successfully coated on the surface of spherical NCA particles, exhibiting improved electrochemical performance. 0.50 wt% Zr（OH）coated NCA delivers a capacity of 197.6 mAh/g at the first cycle and 154.3 mAh/g after 100 cycles with a capacity retention of 78.1% at 1 C rate. In comparison, the pure NCA shows a capacity of 194.6 mAh/g at the first cycle and 142.5 mAh/g after 100 cycles with a capacity retention of 73.2% at 1 C rate. Electrochemical impedance spectroscopy（EIS） results show that the coated material exhibits a lower resistance, indicating that the coating layer can efficiently suppress transition metals dissolution and decrease the side reactions at the surface between the electrode and electrolyte. Therefore, surface coating with amorphous Zr（OH）is a simple and useful method to enhance the electrochemical performance of NCA-based materials for the cathode of LIBs.
基金supported by the Programs of National 973(2011CB935900)NSFC(21231005)+1 种基金MOE(B12015 and 113016A)the Fundamental Research Funds for the Central Universities
文摘In this paper,we report on the preparation of Li2FeSiO4,sintered Li2FeSiO4,and Li2FeSiO4-C composite with spindle-like morphologies and their application as cathode materials of lithium-ion batteries.Spindle-like Li2FeSi04 was synthesized by a facile hydrothermal method with（NH4）2Fe（SO4）2 as the iron source.The spindle-like Li2FeSiO4 was sintered at 600 ℃ for 6 h in Ar atmosphere.Li2FeSiO4-C composite was obtained by the hydrothermal treatment of spindle-like Li2FeSiO4 in glucose solution at 190 ℃ for 3 h.Electrochemical measurements show that after carbon coating,the electrode performances such as discharge capacity and high-rate capability are greatly enhanced.In particular.Li2FeSiO4-C with carbon content of 7.21 wt%delivers the discharge capacities of 160.9 mAh·g-1 at room temperature and 213 mAh·g-1 at45℃（0.1 C）,revealing the potential application in lithium-ion batteries.
文摘B4C, SiC and C, Cu functionally graded-materials (FGMs) have been developed by plasma spraying and hot pressing. Their high-heat flux properties have been investigated by high energy laser and electron beam for the simulation of plasma disruption process of the future fusion reactors, And a study on eroded products of B4C/Cu FGM under transient thermal load of electron beam was performed. In the experiment, SEM and EDS analysis indicated that B4C and SiC were decomposed, carbon was preferentially evaporated under high thermal load, and a part of Si and Cu were melted, in addition, the splash of melted metal and the particle emission of brittle destruction were also found. Different erosive behaviors of carbon-based materials (CBMs) caused by laser and electron beam were also discussed.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10874178,11074093,61205038 and 11274135the National Found for Fostering Talents of Basic Science under Grant No J1103202+2 种基金the Ph.D.Programs Foundation of Ministry of Education of China under Grant No 20120061120011the Open Project of State Key Laboratory of Superhard Materials of Jilin Universitythe State Key Laboratory of Inorganic Synthesis and Preparative Chemistry of Jilin University
文摘High-density Cu2ZnSnS4 （CZTS） materials are prepared via the mechanical alloying and high pressure sintering method using Cu2S, ZnS and SnS2 as the raw materials. The morphological, structural, compositional and electrical properties of the materials are investigated by using x-ray diffraction, scanning electron microscopy, and energy dispersive x-ray spectroscopy, as well as by the Raman scattering and the Hall EFfect measurements. The CZTS synthesized under 5 GPa and 800℃ shows a p-type conductivity, with a resistivity of 9.69 × 10^-2 Ω.cm and a carrier concentration of 1.45 × 10^20 cm-3. It is contributed to by the large grains in the materials reducing the grain boundaries, thus effectively reducing the recombination of the charge carriers.
