Electrochemical characteristics of Sn film prepared by pulse electrodeposition method as negative electrode for lithium secondary batteries

Abstract

In order to improve the cyclability of Sn negative electrode, we tried preparing the Sn film negative electrode by a pulse electrodeposition. Based on the SEM observations, the crystal grains of the Sn film after the pulse electrodeposition were comparatively homogeneous and their grain size was ca. 1 μm. The discharge capacity and the charge-discharge efficiency at the 1st cycle were 679.3 mAh g −1 and 93.0 %, respectively.The charge-discharge tests indicated that the initial electrochemical characteristic of Sn film electrode prepared by a pulse electrodeposition was much better than that of the Sn film electrode prepared by a constant current electrodeposition. The GD-OES profile suggested that Li + ions were easily extracted during the discharge reaction. In addition, it was found that no exfoliation of the film was observed after the 1st discharge though the cracking in the film was observed after the 1st discharge. Consequently, the Sn film electrode prepared by a pulse electrodeposition exhibited a better cyclability for the initial 10 cycles compared to the Sn film electrode prepared by a constant current electrodeposition. By reducing the particle size and repressing the morphological change, the initial electrochemical characteristics were considerably improved. (193 words)

Preparation of Co–Sn alloy film as negative electrode for lithium secondary batteries by pulse electrodeposition method

“…Moreover, for the Sn film electrode prepared by the pulse electrodeposition method, the small reduction wave was observed at ca. 1.6 V in our previous paper [11]. This wave may be due to the reduction of SnO x or the decomposition of the electrolyte.…”

“…The crystal grain size was less than 0.5 μm, which was a little small compared to that of the Sn film (ca. 1.0 μm) [11]. In addition, partial aggregation of deposited particles was observed, which may influence the roughness of the deposit.…”

“…Fig. 6 shows the charge-discharge curves of (a) the Sn film electrode [11] and (b) the It should be noted that a high discharge capacity of the Co 30.5 Sn 69.5 alloy film electrode was obtained with 470.5 mAh g -1 after the 50th cycle, although the discharge capacity of the Co 30.5 Sn 69.5 alloy film electrode at the 1st cycle was lower than that of the Sn film electrode.…”

“…Moreover, due to its high surface area and short ion diffusion length, it is well known that an electrode would show a good kinetic behavior. As a result, the initial cycle performance of the Sn film prepared by the pulse electrodeposition method was significantly better than that of the Sn film prepared by the constant current electrodeposition method [11]. However, it gradually faded after the 11th cycle.…”

“…To easily and simply improve the cyclability of the Sn film electrode, we have selected a constant current pulse electrodeposition method because it is easy to accurately control the element content of the alloy [10] and obtain uniform and fine crystal grains [11]. Moreover, due to its high surface area and short ion diffusion length, it is well known that an electrode would show a good kinetic behavior.…”