In this work,a multi-core-shell-structured LiFePO_(4)@Na_(3) V_(2)(PO_(4))_(3)@C(LFP@NVP@C) composite was successfully designed and prepared to address inferior low-temperature performance of LiFePO_(4) cathode for li...In this work,a multi-core-shell-structured LiFePO_(4)@Na_(3) V_(2)(PO_(4))_(3)@C(LFP@NVP@C) composite was successfully designed and prepared to address inferior low-temperature performance of LiFePO_(4) cathode for lithium-ion batteries.Transmission electron microscopy(TEM) confirms the inner NVP and outer carbon layers coexisted on the surface of LFP particle.When evaluated at low-temperature operation,LFP@NVP@C composite exhibits an evidently enhanced electrochemical performance in term of higher capacity and lower polarization,compared with LFP@C.Even at-10℃ with 0.5 C,LFP@NVP@C delivers a discharge capacity of ca.96.9 mAh-g^(-1) and discharge voltage of ca.3.3 V,which is attributed to the beneficial contribution of NVP coating.NAS ICON-structured NVP with an open framework for readily insertion/desertion of Li+ will effectively reduce the polarization for the electrochemical reactions of the designed LFP@NVP@C composite.展开更多
The Al-2.5C master alloy is prepared to investigate the effect of the Al4C3 particle size distribution on the refining efficiency of the AZ31 alloy. The results indicate that the Al4C3 particles are potent nucleation ...The Al-2.5C master alloy is prepared to investigate the effect of the Al4C3 particle size distribution on the refining efficiency of the AZ31 alloy. The results indicate that the Al4C3 particles are potent nucleation substrates for primary α-Mg grains. With 1.0 wt% master alloy addition, the grain size is reduced from 204 to 70 μm. The grain refining efficiency of the Al4C3 particles on the AZ31 alloy is calculated to be 0.04%-0.75%. Such low refining efficiency is mainly attributed to the size distribution of the Al4C3 particles. The particle sizes are in the range from 0.18 to 7.08 μm, and their distribution is well fitted by a log-normal function. The optimum particle size range for significant grain refinement is proposed to be around 5.0-7.08 μm in the present conditions.展开更多
基金the financial support from the National Natural Science Foundation of China(Nos.51874051,52111530139)the Science and Technology Plan Project of Changzhou,China(No.CQ20D2EHPA034)+1 种基金the Guangxi Natural Science Foundation,China(Nos.2018GXNSFAA281184,2019GXNSFAA245046)Key Laboratory of New Processing Technology for Nonferrous Metal&Materials,Ministry of Education,China(No.20KF-4,20AA-18)。
基金financially supported by the National Natural Science Foundation of China(No.51902036)the Natural Science Foundation of Chongqing Science&Technology Commission(No.cstc2019jcyj-msxm1407)+5 种基金the Natural Science Foundation of Chongqing Technology and Business University(No.1952009)the Science and Technology Research Program of Chongqing Municipal Education Commission(Nos.KJQN201900826 and KJQN201800808)the Venture&Innovation Support Program for Chongqing Overseas Returnees(No.CX2018129)the Innovation Group of New Technologies for Industrial Pollution Control of Chongqing Education Commission(No.CXQT19023)the Engineering and Physical Sciences Research Council(EPSRC)(No.EP/S032886/1)the Key Disciplines of Chemical Engineering and Technology in Chongqing Colleges and Universities during the 13th Five Year Plan。
文摘In this work,a multi-core-shell-structured LiFePO_(4)@Na_(3) V_(2)(PO_(4))_(3)@C(LFP@NVP@C) composite was successfully designed and prepared to address inferior low-temperature performance of LiFePO_(4) cathode for lithium-ion batteries.Transmission electron microscopy(TEM) confirms the inner NVP and outer carbon layers coexisted on the surface of LFP particle.When evaluated at low-temperature operation,LFP@NVP@C composite exhibits an evidently enhanced electrochemical performance in term of higher capacity and lower polarization,compared with LFP@C.Even at-10℃ with 0.5 C,LFP@NVP@C delivers a discharge capacity of ca.96.9 mAh-g^(-1) and discharge voltage of ca.3.3 V,which is attributed to the beneficial contribution of NVP coating.NAS ICON-structured NVP with an open framework for readily insertion/desertion of Li+ will effectively reduce the polarization for the electrochemical reactions of the designed LFP@NVP@C composite.
基金supported by the National Key Research and Development Program of China(No.2016YFB0701204)the project(DUT15JJ(G)01)supported by the Fundamental Research Funds for the Central Universities
文摘The Al-2.5C master alloy is prepared to investigate the effect of the Al4C3 particle size distribution on the refining efficiency of the AZ31 alloy. The results indicate that the Al4C3 particles are potent nucleation substrates for primary α-Mg grains. With 1.0 wt% master alloy addition, the grain size is reduced from 204 to 70 μm. The grain refining efficiency of the Al4C3 particles on the AZ31 alloy is calculated to be 0.04%-0.75%. Such low refining efficiency is mainly attributed to the size distribution of the Al4C3 particles. The particle sizes are in the range from 0.18 to 7.08 μm, and their distribution is well fitted by a log-normal function. The optimum particle size range for significant grain refinement is proposed to be around 5.0-7.08 μm in the present conditions.
