Integrated Anode Electrode Composited Cu–Sn Alloy and Separator for Microscale Lithium Ion Batteries

A novel integrated electrode structure was designed and synthesized by direct electrodepositing of Cu–Sn alloy anode materials on the Celgard 2400 separator (Cel-CS electrode). The integrated structure of the Cel-CS electrode not only greatly simplifies the battery fabrication process and increases the energy density of the whole electrode, but also buffers the mechanical stress caused by volume expansion of Cu–Sn alloy active material; thus, effectively preventing active material falling off from the substrate and improving the cycle stability of the electrode. The Cel-CS electrode exhibits excellent cycle performance and superior rate performance. A capacity of 728 mA·h·g(−1) can be achieved after 250 cycles at the current density of 100 mA·g(−1). Even cycled at a current density of 5 A·g(−1) for 650 cycles, the Cel-CS electrode maintained a specific capacity of 938 mA·h·g(−1), which illustrates the potential application prospects of the Cel-CS electrode in microelectronic devices and systems.