Effect of electrode dimensionality and morphology on the performance of Cu₂Sb thin film electrodes for lithium-ion batteries

Although graphitic carbons have been commercially used in lithium-ion batteries for many years, their low crystallographic density limits their use in applications where space is at a premium. Among the alternative anode materials being considered for these applications are Zintl phases and intermetallic insertion anodes. Historically, main-group-metal-based anode materials have had problems with respect to volume expansion experienced on lithiation and its effect on cycle life. In this paper, we report the role of morphology and electrode dimensionality in extending the cycle life of the intermetallic insertion anode Cu₂Sb. We have found that controlling the surface area of the active material and building internal volume into the electrode structure significantly decreases the capacity fade on cycling. The decrease in fade rate may be due to the active material gradient identified within the structure produced by the electrodeposition process. This enhancement in cycling can be attributed to keeping the displaced copper closer to the active particles and to reducing the diffusion distances within the electrode.