The practical application of solid polymer electrolytes in high-energy Li metal batteries is hindered by Li dendrites,electrochemical instability and insufficient ion conductance.To address these issues,flexible compo...The practical application of solid polymer electrolytes in high-energy Li metal batteries is hindered by Li dendrites,electrochemical instability and insufficient ion conductance.To address these issues,flexible composite polymer electrolyte(CPE)membranes with three dimensional(3D)aramid nanofiber(ANF)frameworks are facilely fabricated by filling polyethylene oxide(PEO)-lithium bis(trifluoromethylsulphonyl)imide(Li TFSI)electrolyte into 3D ANF scaffolds.Because of the unique composite structure design and the continuous ion conduction at the 3D ANF framework/PEO-Li TFSI interfaces,the CPE membranes show higher mechanical strength(10.0 MPa),thermostability,electrochemical stability(4.6 V at 60℃)and ionic conductivity than the pristine PEO-Li TFSI electrolyte.Thus,the CPEs display greatly improved interfacial stability against Li dendrites(≥1000 h at 30℃under 0.10 m A cm-2),compared with the pristine electrolyte(short circuit in 13 h).The CPE-based all-solid-state LiFePO4/Li cells also exhibit superior cycling performance(e.g.,130 mA h g-1 with 93%retention after 100 cycles at 0.4 C)than the ANF-free cells(e.g.,82 mA h g-1 with 66%retention).This work offers a simple and effective way to achieve high-performance composite electrolyte membranes with 3D nanofiller framework for promising solid-state Li metal battery applications.展开更多
Antiperovskite compounds Mn3Ag1-xCoxN （x =0.2, 0.5 and 0.8） are synthesized and the doping effect of the magnetic element Co at the Ag site is investigated. The crystal structure is not changed by the introduction o...Antiperovskite compounds Mn3Ag1-xCoxN （x =0.2, 0.5 and 0.8） are synthesized and the doping effect of the magnetic element Co at the Ag site is investigated. The crystal structure is not changed by the introduction of Co. However, with the increase of the content of Co, the spin reorientation gradually disappears and the antiferromagnetic transition changes to the ferromagnetic transition at the elevated temperature when x = 0.8. In addition, all of the magnetic phase transitions at the elevated temperature are always accompanied by the abnormal thermal expansion behaviors and an entropy change. Moreover, when x = 0.8, the coefficient of linear expansion is -1.89 × 10^-6 K^-1 （290-310K, △T =20 K）, which is generally considered as the low thermal expansion.展开更多
基金supported partially by Beijing Natural Science Foundation(L172036)Joint Funds of the Equipment Pre-Research and Ministry of Education(6141A020225)+2 种基金Par-Eu Scholars Program,Science and Technology Beijing 100 Leading Talent Training Project,Beijing Municipal Science and Technology Project(Z161100002616039)China Postdoctoral Science Foundation(2018M631419)the Fundamental Research Funds for the Central Universities(2017ZZD02 and 2019QN001).
文摘The practical application of solid polymer electrolytes in high-energy Li metal batteries is hindered by Li dendrites,electrochemical instability and insufficient ion conductance.To address these issues,flexible composite polymer electrolyte(CPE)membranes with three dimensional(3D)aramid nanofiber(ANF)frameworks are facilely fabricated by filling polyethylene oxide(PEO)-lithium bis(trifluoromethylsulphonyl)imide(Li TFSI)electrolyte into 3D ANF scaffolds.Because of the unique composite structure design and the continuous ion conduction at the 3D ANF framework/PEO-Li TFSI interfaces,the CPE membranes show higher mechanical strength(10.0 MPa),thermostability,electrochemical stability(4.6 V at 60℃)and ionic conductivity than the pristine PEO-Li TFSI electrolyte.Thus,the CPEs display greatly improved interfacial stability against Li dendrites(≥1000 h at 30℃under 0.10 m A cm-2),compared with the pristine electrolyte(short circuit in 13 h).The CPE-based all-solid-state LiFePO4/Li cells also exhibit superior cycling performance(e.g.,130 mA h g-1 with 93%retention after 100 cycles at 0.4 C)than the ANF-free cells(e.g.,82 mA h g-1 with 66%retention).This work offers a simple and effective way to achieve high-performance composite electrolyte membranes with 3D nanofiller framework for promising solid-state Li metal battery applications.
基金Supported by the National Natural Science Foundation of China under Grant No 51172012the Fundamental Research Funds for the Central Universities
文摘Antiperovskite compounds Mn3Ag1-xCoxN （x =0.2, 0.5 and 0.8） are synthesized and the doping effect of the magnetic element Co at the Ag site is investigated. The crystal structure is not changed by the introduction of Co. However, with the increase of the content of Co, the spin reorientation gradually disappears and the antiferromagnetic transition changes to the ferromagnetic transition at the elevated temperature when x = 0.8. In addition, all of the magnetic phase transitions at the elevated temperature are always accompanied by the abnormal thermal expansion behaviors and an entropy change. Moreover, when x = 0.8, the coefficient of linear expansion is -1.89 × 10^-6 K^-1 （290-310K, △T =20 K）, which is generally considered as the low thermal expansion.
