A 3D printed freestanding ZnSe/NC anode for Li-ion microbatteries

The rapid development of micro/nanomanufactured integrated microsystems in recent years requires high performance micro energy storage devices (MESDs). Li-ion microbatteries (LIMBs) are the most studied MESDs, but the low mass loading of active materials and the less-than-perfect energy density hinder their further application. A 3D printed ZnSe/N-doped carbon (ZnSe/NC) composite electrode was designed and fabricated by extrusion-based 3D printing and a post-treatment strategy for use as the anode of LIMBs. The high capacity ZnSe nanoparticles are confined in the NC, where the NC not only improves the conductivity but also acts as a buffer layer to reduce the volume expansion and provide additional active sites for electrochemical reactions. The interconnected design of the 3D printed electrode is good for fast mass transfer and ion transport. A freestanding 3D printed ZnSe/NC electrode with a high mass loading of 3.15 mg cm⁻² was achieved by direct ink printing, which had a superior energy density and decent reversibility in high-power LIMBs. This strategy can be used for other high-performance electrodes to achieve a high-mass-loading of active materials for microbatteries, opening up a new way to construct advanced MESDs.