Co2＋-doped LiFePO4/C composite material was prepared by solid-state synthesis method using Fe2O3,Li2CO3 and NH4H2PO4 as the starting materials.The structures and elec-trochemical performance of samples were studied b...Co2＋-doped LiFePO4/C composite material was prepared by solid-state synthesis method using Fe2O3,Li2CO3 and NH4H2PO4 as the starting materials.The structures and elec-trochemical performance of samples were studied by XRD,SEM and constant current charge-discharge method.The results showed that the Co2＋ doping did not change the crystal structure of LiFePO4.The unit cell volume changed with the increase of Co2＋,and reached the maximum at x = 0.04.The LiFe0.96Co0.04PO4/C sample proved the best electrochemical properties.Its initial discharge capacity was 138.5 mA·h /g at 1 C rate.After 30 cycles,the capacity remained 127.7 mA·h /g,and the capacity retention rate was 92.2%.展开更多
The comparative study of LiNi_(0.8)Co_(0.2)O_2 and LiNi_(0.75)A_(0.25)O_2 wascarried out by X-ray diffraction (XRD) and electrochemical methods. The results show that Co and Aldoping suppress the phase transition duri...The comparative study of LiNi_(0.8)Co_(0.2)O_2 and LiNi_(0.75)A_(0.25)O_2 wascarried out by X-ray diffraction (XRD) and electrochemical methods. The results show that Co and Aldoping suppress the phase transition during charge-discharge. The experiments indi cate thatLiNi_(0.75)Al_(0.25)O_2 has the better cycle-ability and over-charge resistance comparing withLiNi_(0.8)Co_(0.2)O_2. The interfacial behavior was studied by use of electrochemical impedancespectroscopy (EIS). The results show that LiNi_(0.75)Al_(0.25)O_2 has a slightly larger polarizationcharacter than LiNi_(0.8)Co_(0.2)O_2.展开更多
The low cost and profusion of sodium resources make sodium-ion batteries(SIBs)a potential alternative to lithium-ion batteries for grid-scale energy storage applications.However,the use of conventional cathode materia...The low cost and profusion of sodium resources make sodium-ion batteries(SIBs)a potential alternative to lithium-ion batteries for grid-scale energy storage applications.However,the use of conventional cathode materials for Na-ion intercalation/deintercalation cannot satisfy the requirements of high-powered and long lifespan performance due to multiphase transition and lattice confinement.展开更多
基金Sponsored by the Graduate Innovation Fund of Shaanxi University of Science and Technology
文摘Co2＋-doped LiFePO4/C composite material was prepared by solid-state synthesis method using Fe2O3,Li2CO3 and NH4H2PO4 as the starting materials.The structures and elec-trochemical performance of samples were studied by XRD,SEM and constant current charge-discharge method.The results showed that the Co2＋ doping did not change the crystal structure of LiFePO4.The unit cell volume changed with the increase of Co2＋,and reached the maximum at x = 0.04.The LiFe0.96Co0.04PO4/C sample proved the best electrochemical properties.Its initial discharge capacity was 138.5 mA·h /g at 1 C rate.After 30 cycles,the capacity remained 127.7 mA·h /g,and the capacity retention rate was 92.2%.
文摘The comparative study of LiNi_(0.8)Co_(0.2)O_2 and LiNi_(0.75)A_(0.25)O_2 wascarried out by X-ray diffraction (XRD) and electrochemical methods. The results show that Co and Aldoping suppress the phase transition during charge-discharge. The experiments indi cate thatLiNi_(0.75)Al_(0.25)O_2 has the better cycle-ability and over-charge resistance comparing withLiNi_(0.8)Co_(0.2)O_2. The interfacial behavior was studied by use of electrochemical impedancespectroscopy (EIS). The results show that LiNi_(0.75)Al_(0.25)O_2 has a slightly larger polarizationcharacter than LiNi_(0.8)Co_(0.2)O_2.
基金the National Key Research Program of China(no.2016YFB0901500)the National Science Foundation of China(nos.21673165 and 2197210821333007)the supercomputing system in the Supercomputing Center of Wuhan University for their financial support.
文摘The low cost and profusion of sodium resources make sodium-ion batteries(SIBs)a potential alternative to lithium-ion batteries for grid-scale energy storage applications.However,the use of conventional cathode materials for Na-ion intercalation/deintercalation cannot satisfy the requirements of high-powered and long lifespan performance due to multiphase transition and lattice confinement.
