Fabrication of 3D silicon anode by inkjet printing: Opportunities and challenges

The pressing issue of climate change and the acceleration of global warming have prompted increased concerns about CO emissions and the need for sustainable energy solutions. The transition to electric vehicles (EVs) is crucial in achieving a sustainable and greener future for our planet. Lithium-ion batteries (LIBs) are the most common storage energy systems used in the fabrication of EVs. However, further advancements are needed to improve their energy density, power density, safety, and cost. One promising approach is to replace conventional graphite anodes with silicon, offering higher capacity and environmental friendliness. This study explores the fabrication of three-dimensional (3D) silicon anodes using drop-on-demand (DOD) inkjet printing (IJP), a promising additive manufacturing technique. The formulation of stable aqueous inks for LIB anodes is presented, highlighting their potential for scalable production. The article addresses the difficulties encountered in developing printable inks for DOD IJP and assesses the electrochemical performance of these ink formulations. Inks containing carbon-coated silicon nanoparticles and PEDOT:PSS result in electrodes that attained the cutoff lithiation capacity of 2000 mAh g with no observed capacity degradation over time. In contrast, anodes composed of pure silicon demonstrate a capacity decay after 75 cycles, proving the advantages of utilizing a Si/Carbon core-shell structure. The printability tests are presented, revealing the instabilities of the drop generation process, and the importance of particle surface chemistry. While it is possible to use IJP with the formulated anode inks, further optimization of the technology is necessary for practical implementation.