Influence of active material content on the performance of direct ink printed lithium-ion battery cathodes

Driven by the growing demand for small devices due to the Internet-of-Things concept, lithium-ion batteries (LIBs) represent an essential technology to store energy for portable electronics with specific sizes/requirements. The LIBs' performance is highly dependent on the electrodes' composition/microstructure, particularly the cathode. In this work, it is investigated the influence of different ratios between active material C-LiFePO 4 (80–93 %), polymer binder Poly(vinylidene-fluoride) (3.5–10 %) and conductive additive Carbon-black C45 (3.5–10 %) on the electrochemical behaviour of cathodes fabricated by Direct Ink Writing (DIW) printing technique. Inks with suitable rheology for DIW printing process are prepared. The different formulations have been evaluated, with particular attention to discharge capacity, cycling stability and conductivity. Among the tested compositions, the cathode containing 85 % of active material and 7.5 % each of polymer binder and conductive additive exhibited the highest performance (150.2 mAh.g −1 , C/8-rate), demonstrating improved capacity retention at high rate (46.3 %, 2C-rate) and stable cycling behaviour. Morphological analysis confirmed a uniform components’ dispersion with absence of agglomeration. Additionally, DIW proved to be a promising/scalable method for cathode production, offering advantages in terms of material efficiency, structural control, and sustainability. These findings underscore the importance of optimizing cathode formulation and fabrication methods to enhance the performance of next-generation LIBs. • The prepared battery cathode inks are compatible with Direct-ink writing technique. • Printed cathodes 85/7.5/7.5 reach a capacity value of 150.2 mAh.g −1 at C/8-rate. • DIW technique proved to be a suitable and scalable method for cathode production. • Printed cathode show improved performance compared with doctor blade electrodes.