Clog-Free, Low-Cost, and Uniform Electrode Inks for 3D Printed Lithium-Ion Batteries

Direct ink writing (DIW) is a promising additive manufacturing technique for fabricating shape-customized lithiumion batteries (LIBs) due to its simplicity, material compatibility, and shapeability. A key component of DIW is the electrode inks with appropriate rheology and clog-free property for threedimensional (3D) printed LIBs. Here, a series of clog-free printable electrode inks for LIBs are developed by a practical and universal approach with multiple ball-milled processes. The inks can be used for an ultralong printing process without blockage, showing great printability and rheological properties. The sizes of the electrode particles and secondary aggregates both decrease in the inks, making uniform particle distribution in the dried printed electrodes. Particle transport simulations in the ink flow field also illustrate that smaller particles are less likely to clog the nozzle inlet. Meanwhile, the 3D printed electrodes demonstrate stable cycling stability and rate capability compared to conventional electrodes, showing average discharge capacities of 158.3, 145.8, and 147.4 mAh g-1 in 100 cycles for Li4Ti5O12, LiNi0.815Co0.15Al0.035O2, and LiFePO4 half-cells, respectively. The full cells assembled with printed electrodes also exhibit a comparable discharge capacity. This approach offers a universal and low-cost strategy to manufacture complex electrode structures for customizable energy storage devices.