Direct ink writing of metal-based electrocatalysts for Li-S batteries with efficient polysulfide conversion

Thanks to the significantly higher energy density compared with universal commercialized Li-ion batteries, lithium-sulfur (Li-S) batteries are being investigated for use in prospective energy storage devices. However, the inadequate electrochemical kinetics of reactants and intermediates hinder commercial utilization. This limitation results in substantial capacity degradation and short battery lifespans, thereby impeding the battery's power export. Meanwhile, the capacity attenuation induced by the undesirable shuttle effect further hinders their industrialization. Considerable effort has been invested in developing electrocatalysts to fix lithium polysulfides and boost their conversion effectively. In the conventional process, the planar electrodes are prepared by slurry-casting, which limits the electron and ion transfer paths, especially when the thickness of the electrodes is relatively large. Compared with traditional manufacturing methods, direct ink writing (DIW) technology offers unique advantages in both geometry shaping and rapid prototyping, and even complex three-dimensional structures with high sulfur loading. Hence, this review presents a detailed description of the current developments in terms of Li-S batteries in DIW of metal-based electrocatalysts. A thorough exploration of the behavior chemistry of electrocatalysis is provided, and the adhibition of metal-based catalysts used for Li-S batteries is summarized from the aspect of material usage and performance enhancement. Then, the working principle of DIW technology and the requirements of used inks are presented, with a detailed focus on the latest advancements in DIW of metal-based catalysts in Li-S battery systems. Their challenges and prospects are discussed to guide their future development.