Sn-based Anode-materials with Macroporous Metal Films for Secondary Lithium-ion Batteries

摘要

Anode properties of Sn films on macroporous (m-) metal films (Sn(N)/m-M films, N: condition of electrolytic deposition, S (10 mA cm-2, 2 min) or L (2 mA cm-2, 10 min), M: Co or Ni) for secondary lithium-ion batteries have been investigated. Sn(N)/m-M films were fabricated as follows. First, polymethylmethacrylate (PMMA) microspheres (ca. 800 nm in diameter) as a macropore template were stacked on a Cu foil by dip-coating. m-Co or m-Ni film was obtained after electrolytic deposition on the PMMA template film in a constituent metal sulfate aqueous solution and subsequent removal of PMMA microspheres in acetone. Thereafter, Sn was electrochemically deposited on m-Co or m-Ni at condition of S or L, and then it was heat-treated at 200℃ for 20 h in vacuo. First discharge capacity of 4 kinds of Sn(N)/m-M films obtained (550~750 mA h g-1) was lower than that of the pure Sn film without m-M (ca. 900 mA h g-1). However, charge-discharge characteristics of their anodes were drastically improved by the introduction of m-M, and the Sn(L)/m-Co film showed the largest discharge capacity (ca. 600 mA h g-1 even at 30th discharge) among the films tested.