One-minute deposition of micrometre-thick porous Si anodes for lithium ion batteries

摘要

We report the rapid vapour deposition of 3-14 mu m-thick porous Si anodes on Cu current collectors in 10-60 s. Such rapid deposition was achieved by heating the Si source to over 2000 degrees C, well above the melting point of Si, while the porous structure was realized in the deposited Si films by keeping the Cu collector at a much lower temperature of 100-500 degrees C. The adhesion between the Cu collectors and Si films was enhanced by forming a CuSix intermixed layer by post-deposition annealing as well as surface treatment of the Cu collectors. Half-cell measurements showed that the porous Si anodes without post-annealing degraded in a few cycles. A markedly improved cycle performance (1000 mA h g(Si)(-1) and 0.66 mA h cm(anode)(-2) at the anode for the 50th cycle) was achieved for post-annealed 3.5 mu m-thick porous Si films. Rapid vapor deposition of micrometre-thick porous Si films using inexpensive, safe Si powder is a practical route to fabricate high-capacity anodes for lithium ion batteries.