ChemInform Abstract: Active/Inactive Nanocomposites as Anodes for Li‐Ion Batteries.

Abstract

Active/Inactive Nanocomposites as Anodes for Li-Ion Batteries. -Composites consisting of active grains which can alloy with Li and inactive grains which cannot are made by mechanical alloying of elemental powders. The inactive grains act as matrix to hold the active grains as they repeatedly alloy with Li during the operation of a Li battery. A microscopic mixture of 25% Sn 2 Fe (active) and 75% SnFe 3 C (inactive) shows a volumetric capacity for Li which is twice that of the graphitic materials. The composite retains its capacity for many charge/discharge cycles and, therefore, materials like this may be the anodes of choice for the next generation of high-energy lithium batteries. -(MAO, O.; TURNER, R. L.; COURTNEY, I. A.; FREDERICKSEN, B. D.; BUCKETT, M. I.; KRAUSE, L. J.; DAHN, J. R.; Electrochem. Solid-State Lett. 2 (1999) 1, 3-5; Dep. Phys., Dalhousie Univ., Halifax, Nova Scotia B3H 3J5, Can.; EN)

Room temperature crystallization kinetics of amorphous Cu6Sn5+C alloys

“…However, comparison of the functional form of Eq. (8) with Fig. 7 shows that the activation energy (as inferred by the Avrami-Johnson-Mehl equation) is approximately linearly dependent on the atomic fraction C in thin film amorphous Cu 6 Sn 5 + C samples.…”

“…Work in this area has focused primarily on Cu 6 Sn 5 with an effort to create nano-sized Cu-Sn grains to help reduce damaging effects caused by stress/strain due to volume changes upon lithiation [1,8,9]. It is widely believed that amorphous or nanostructured materials are best suited for high-volume expansion alloys such as Sn to further reduce the effects of expansion and contraction [10].…”

Electrolyte and Solid-Electrolyte Interphase Layer in Lithium-Ion Batteries

“…The volume shrink of the delithiated oxide, also evidenced by ToF-SIMS after deconversion, is thought to generate the loss of fragments of the SEI layer due to compressive stress. Alloying-type materials are considered to be very promising alternative negative electrodes for LIBs due to their high capacity and good cycling ability [Winter et al, 1999;Huggins, 1999;Mao et al, 1999]. Despite the progress of electrochemical performance of alloying materials such as Sn-Co electrodes, the mechanisms of interfacial reactions, especially the formation, the stability, the variation and the composition of the SEI layer are not yet completely known.…”

Thin films of Cu2Sb and Cu9Sb2 as anode materials in Li-ion batteries

“…Due to the significant changes in the volume of these materials associated with the lithiation and delithiation processes, much work is presently carried out to study how to circumvent this problem [3] using for instance, metal oxides [3][4][5][6][7][8][9][10] where the oxide serves as a buffering matrix during the lithiation process, or by utilising nanoparticles to minimize the effects of the volume changes [11][12][13]. Other approaches involve embedding the active electrode material in a composite matrix [14][15][16], the use of amorphous alloys [17][18][19], or intermetallic systems (A x B y ) which have a strong structural relationship to that of their lithiated products [20][21][22]. In these materials, both metals can either be active with respect to lithium (see e.g.…”