Ba0.8Sr0.2FeO3-δhas been surface-modified by the lithium-ion conductor Li1.4Al0.4Ti1.6(PO4)3via a facile mechanical fusion method. The annealing temperature during coating process shows a strong impact on the surface...Ba0.8Sr0.2FeO3-δhas been surface-modified by the lithium-ion conductor Li1.4Al0.4Ti1.6(PO4)3via a facile mechanical fusion method. The annealing temperature during coating process shows a strong impact on the surface morphology and chemical composition of Li(Ni0.6 Co0.2 Mn0.2)O2. The 600-?C annealed material exhibits the best cyclic stability at high charging cut-off voltage of 4.5 V(versus Li+/Li) with the capacity retention of 90.9% after 100 cycles, which is much higher than that of bare material(79%). Moreover, the rate capability and thermal stability are also improved by Li1.4Al0.4Ti1.6(PO4)3coating. The enhanced performance can be attributed to the improved stability of interface between Ba0.8Sr0.2FeO3-δand electrolyte by Li1.4Al0.4Ti1.6(PO4)3modification. The results of this work provide a possible method to design reliable cathode materials to achieve high energy density and long cycle life.展开更多
A method of concentration analysis based on X-ray photoelectron spectroscopy (XPS) results was introduced. The concentration of Ce-rich conversion coating on the anodized Al based metal matrix composites AI6061/SiCp w...A method of concentration analysis based on X-ray photoelectron spectroscopy (XPS) results was introduced. The concentration of Ce-rich conversion coating on the anodized Al based metal matrix composites AI6061/SiCp was then studied according to this method. The results revealed that the Ce conversion coating on the anodized AI6061/SiCp consisted of Al oxide, Ce oxide and Ce hydroxide. The state of Ce element exhibited the mixture of Ce3+ and Ce4+. Some of Cell I was oxidized to be CelV in the outer layer coating.展开更多
Epoxy zinc rich coatings containing clay nanoparticles were prepared and the effect of clay content on the cathodic protection performance of the coatings was evaluated by electrochemical impedance spectroscopy（EIS）...Epoxy zinc rich coatings containing clay nanoparticles were prepared and the effect of clay content on the cathodic protection performance of the coatings was evaluated by electrochemical impedance spectroscopy（EIS） and immersion test. Open circuit potential（OCP） measurements and immersion tests were also carried out to better understand the behavior of zinc rich coating. EIS and OCP measurements showed that addition of 1 wt% clay improved the cathodic protection duration and sacrificial properties of the epoxy zinc rich coating. Transmission electron microscopy（TEM） photographs confirmed that clay nanoparticles were successfully dispersed in the coating matrix loaded with 1 wt% clay. Immersion test results indicated that addition of 1 wt% clay nanoparticles in zinc rich epoxy coatings increased the cathodic protection ability of coatings.展开更多
Surface deterioration occurs more easily in nickel-rich cathode materials with the increase of nickel content.To simultaneously pre-vent deterioration of active cathode materials and improve the electrochemical perfor...Surface deterioration occurs more easily in nickel-rich cathode materials with the increase of nickel content.To simultaneously pre-vent deterioration of active cathode materials and improve the electrochemical performance of the nickel-rich cathode material,the surface of nickel-rich LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)cathode material is decorated with the stable structure and conductive Li_(3)PO_(4)by a facile method.The LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)-1wt%,2wt%,3wt%Li_(3)PO_(4)samples deliver a high-capacity retention of more than 85%after 100 cycles at 1 C under a high voltage of 4.5 V.The effect of different coating amounts(0-5wt%)for the LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)cathode is analyzed in detail.Results show that 2wt%coating of Li_(3)PO_(4)gives better performance compared to other coating concentrations.Detailed analysis of the structure of the samples during the charge−discharge process is performed by in-situ X-ray diffraction.It is indicated that the modification for LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)cathode could protect the well-layered structure under high voltages.In consequence,the electrochemical performance of modified samples is greatly improved.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
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFB0102004)the National Natural Science Foundation of China(Grant No.51822211)the State Grid Technology Project,China(Grant No.DG71-17-010)
文摘Ba0.8Sr0.2FeO3-δhas been surface-modified by the lithium-ion conductor Li1.4Al0.4Ti1.6(PO4)3via a facile mechanical fusion method. The annealing temperature during coating process shows a strong impact on the surface morphology and chemical composition of Li(Ni0.6 Co0.2 Mn0.2)O2. The 600-?C annealed material exhibits the best cyclic stability at high charging cut-off voltage of 4.5 V(versus Li+/Li) with the capacity retention of 90.9% after 100 cycles, which is much higher than that of bare material(79%). Moreover, the rate capability and thermal stability are also improved by Li1.4Al0.4Ti1.6(PO4)3coating. The enhanced performance can be attributed to the improved stability of interface between Ba0.8Sr0.2FeO3-δand electrolyte by Li1.4Al0.4Ti1.6(PO4)3modification. The results of this work provide a possible method to design reliable cathode materials to achieve high energy density and long cycle life.
基金This work has been carried out with the support of The Chinese Postdoctoral Science Fund and The Special Funds for the Major State Basic Research Projects G19990650.
文摘A method of concentration analysis based on X-ray photoelectron spectroscopy (XPS) results was introduced. The concentration of Ce-rich conversion coating on the anodized Al based metal matrix composites AI6061/SiCp was then studied according to this method. The results revealed that the Ce conversion coating on the anodized AI6061/SiCp consisted of Al oxide, Ce oxide and Ce hydroxide. The state of Ce element exhibited the mixture of Ce3+ and Ce4+. Some of Cell I was oxidized to be CelV in the outer layer coating.
文摘Epoxy zinc rich coatings containing clay nanoparticles were prepared and the effect of clay content on the cathodic protection performance of the coatings was evaluated by electrochemical impedance spectroscopy（EIS） and immersion test. Open circuit potential（OCP） measurements and immersion tests were also carried out to better understand the behavior of zinc rich coating. EIS and OCP measurements showed that addition of 1 wt% clay improved the cathodic protection duration and sacrificial properties of the epoxy zinc rich coating. Transmission electron microscopy（TEM） photographs confirmed that clay nanoparticles were successfully dispersed in the coating matrix loaded with 1 wt% clay. Immersion test results indicated that addition of 1 wt% clay nanoparticles in zinc rich epoxy coatings increased the cathodic protection ability of coatings.
基金This work was financially supported by the Guangdong Key Laboratory of Battery Safety(No.2019B121203008)the National Natural Science Foundation of China(No.52072036),NSAF(No.U1930113)+2 种基金the Beijing Natural Science Foundation(No.L182022)the 13th Five-Year Plan of Advance Research and Sharing Techniques by Equipment Department(No.41421040202)the China Postdoctoral Science Foundation(No.2021TQ0034).
文摘Surface deterioration occurs more easily in nickel-rich cathode materials with the increase of nickel content.To simultaneously pre-vent deterioration of active cathode materials and improve the electrochemical performance of the nickel-rich cathode material,the surface of nickel-rich LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)cathode material is decorated with the stable structure and conductive Li_(3)PO_(4)by a facile method.The LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)-1wt%,2wt%,3wt%Li_(3)PO_(4)samples deliver a high-capacity retention of more than 85%after 100 cycles at 1 C under a high voltage of 4.5 V.The effect of different coating amounts(0-5wt%)for the LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)cathode is analyzed in detail.Results show that 2wt%coating of Li_(3)PO_(4)gives better performance compared to other coating concentrations.Detailed analysis of the structure of the samples during the charge−discharge process is performed by in-situ X-ray diffraction.It is indicated that the modification for LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)cathode could protect the well-layered structure under high voltages.In consequence,the electrochemical performance of modified samples is greatly improved.
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.
