Electrical conductivity of Cu-Li alloys

The electrical conductivity of Cu-Li alloys was studied. And the distribution of electrons near Fermi surface was detected by synchrotron radiation instrument. The results show that the electrical conductivity of Cu-Li alloys decreases from 5.22 X 10(-9) S/m to 3.69 X 10(-9) S/m with the increase of Li content. Li can decrease the oxygen, sulfur and other impurities content in commercial Cu, but Li dissolved in Cu lattice leads to distortion of Cu lattice from 0.005%-0.050%, affects the valence band of Cu, increases the binding energy of surface electron, and decreases the electron density of Fermi surface simultaneously. So the electrical conductivity decreases gradually with the increase of Li content.

Enhanced efficiency and stability of 3.3 V Cu-Li batteries by tuning the cation-anion interaction in the electrolyte

Cu-Li battery with Cu metal cathode and Li metal anode is a candidate for next-generation energy storage system.While self-discharge of the battery can be suppressed with an anion exchange membrane,the voltage polarization depends strongly on the electrolyte.Specifically,when an electrolyte with 3 M LiTFSI(lithium bis(trifluoromethanesulfonyl)imide)in dimethyl carbonate(DMC)is used,overpotential increases with cycling.In this work,we reveal why the voltage polarization changes,and reduce and stabilize it by replacing DMC solvent with a mixed solvent composed of dimethoxyethane(DME)and propylene carbonate(PC).The new electrolyte has higher ionic conductivity and stable solvation structure with more free TFSI-anions upon cycling,which also facilitates uniform plating of metal ions on the metal electrodes.These characteristics enable a stable Cu-Li battery with minimal change in overpotential for more than 1500 cycles at a current density of 2 m A cm^(-2).

Effect of lithium on the casting microstructure of Cu-Li alloys

The effect of lithium on the casting microstructure of Cu-Li alloys was studied via the Wild MPS 46 Automatic camera, Deitz Diaplan, and scanning electron microscope. The result shows that trace lithium added to copper coarsens the grains of Cu-Li alloys in equiaxed crystal area because of the excellent purification effect. With the amount of lithium increasing, the average grain size increases sharply. But when the amount of lithium increases more, the average grain size decreases instead. At the same time, the typical dentritic crystal area of copper is diminished when lithium is added to pure copper.

Electrochemical solid-state amorphization in the immiscible Cu-Li system

As a typical immiscible binary system, copper (Cu) and lithium (Li) show no alloying and chemical intermixing under normal circumstances. Here we show that, when decreasing Cu nanoparticle sizes into ultrasmall range, the nanoscale size effect can play a subtle yet critical role in mediating the chemical activity of Cu and therefore its miscibility with Li, such that the electrochemical alloying and solidstate amorphization will occur in such an immiscible system. This unusual observation was accomplished by performing in-situ studies of the electrochemical lithiation processes of individual CuO nanowires inside a transmission electron microscopy (TEM). Upon lithiation, CuO nanowires are first electrochemically reduced to form discrete ultrasmall Cu nanocrystals that, unexpectedly, can in turn undergo further electrochemical lithiation to form amorphous Cu Lixnanoalloys. Real-time TEM imaging unveils that there is a critical grain size (ca. 6 nm), below which the nanocrystalline Cu particles can be continuously lithiated and amorphized. The possibility that the observed solid-state amorphization of Cu-Li might be induced by electron beam irradiation effect can be explicitly ruled out; on the contrary, it was found that electron beam irradiation will lead to the dealloying of as-formed amorphous Cu Lixnanoalloys.