Fabrication of binder-free SnO_2 nanoparticle electrode for lithium secondary batteries by electrophoretic deposition method

摘要

We tried fabricating a binder-free co-deposited film electrode consisting of SnO_2 nanoparticles (nano-SnO_2) and acetylene black (AB) particles by an electrophoretic deposition (EPD) method. By cathodically depositing on a copper foil when employing an acetone bath, the co-deposited film consisting of nano-SnO_2 and AB could be fabricated. SEM/EDX indicated that the roughness of the co-deposited film was approximately 1 μm and the nano-SnO_2 particles and the AB particles were uniformly deposited. The weight percent of the nano-SnO_2 in the co-deposited film could be controlled in the range from 87.80 to 93.64 wt.%. The galvanostatic charge-discharge tests indicated that the discharge capacity and the charge-discharge efficiency of the co-deposited film (nano-SnO_2:AB = 93.64:6.36 wt.%) at the 1st cycle were 887 mAh g~(-1) and 48.8% at 0.1C, respectively; the discharge capacity after the 50th cycle was 504 mAh g~(-1). It has been considered that the reverse reaction of the conversion reaction would occur during discharging because the discharge capacity at the 1st cycle was higher than the theoretical capacity of SnO_2 (783 mAh g~(-1)). Thus it has been clarified that the binder-free co-deposited film could operate as a negative electrode for lithium secondary batteries.