The electrochemical properties of copper sulfide as cathode material for rechargeable sodium cell at room temperature

The sodium/copper sulfide (Na/Cu2S) rechargeable batteries are investigated using 1 M NaCF3SO3-TEGDME liquid electrolyte at room temperature. The first discharge curve of Na/Cu2S cells shows a slope shape without plateaus potential region. The first discharge capacity is 294 mAh g−1 and decreases to 220 mAh g−1 after 20 cycles. The discharge process can be explained by intercalation of sodium into Cu2S phase without phase separation of Cu2S.