Flexible inkjet-printed lithium-ion batteries with Ti3C2Tx current collector

The Internet of Things (IoT) market is a quickly growing field that has great economic potential and attracts interest from researchers. Progress in this field relies on the ability to integrate smart devices with everyday objects and instruments. Therefore, energy storage plays a critical role in powering these devices. In this context, inkjet printing of batteries can be framed as a potentially innovative fabrication technique that combines the benefits of thin-film technology for lightness, mechanical flexibility, and ease of integration. The main bottleneck to obtaining a full inkjet-printed battery is printing the current collector (CC), whose role is to electrically bridge the electrodes to an external circuit and mechanically support the electrodes. A simple ink formulation based on hydrophilic and electronically conductive Ti3C2Tx MXene has been proposed for printing current collectors in this work. We have analyzed substrate compatibility and the necessity of the adopted device configurations. Also, a fully printed battery with good flexibility has been produced and showed no performance degradation upon bending. The results of this study show that Ti3C2Tx MXene is a promising candidate for flexible printed current collectors. However, an improvement in the electrochemical performance, in particular the areal capacity of the device, is still necessary for practical use. This may be achieved by minimizing the spacing between the electrodes using a printer with a higher resolution.