In situ atomic force microscopy measurements of patterned amorphous Sn-Co-C sputtered films reacting with Li in an electrochemical cell have been made. Prismatic-shaped patches of Sn0.34Co0.19C0.47 were found to undergo reversible volume expansion of 175 +/- 5% [(V-final -V-initial)/V-initial] without fracture. The a-Sn0.34Co0.19C0.47 was found to have a reversible specific capacity of 700 +/- 10 mAh/g when cycled vs a Li metal negative electrode. (c) 2007 The Electrochemical Society.