3D Printing Integrated Lipophilic Additives Engineering to Enhance Wettability of Thick Electrodes Achieving High...

The poor diffusion and transfer kinetics of Li⁺ is the critical bottleneck for energy and power density in thick electrodes. Here, we develop a 3D-printed magnesium silicate for solid-state integrated lipophilic additive engineering technology to fabricate thick electrodes, effectively mitigating concentration polarization caused by the Li⁺ gradient distribution. By grafting cetyltrimethylammonium, a cationic surfactant-modified inorganic filler (LCN) is prepared, which is added into the LiFePO₄ (LFP) slurry for 3D printing into a porous 810 μm thick LFP cathode. The introduced alkyl-lipophilic groups endow the cathode with higher adsorption energy, shortening the wetting time of the electrolyte by 75%. Moreover, the alkylammonium electron-donating groups not only increase the electron cloud density around O^2- within the electrode but also decrease the crystallinity of the binder, enhancing the Li⁺ transfer and transport kinetics. Furthermore, the 3D network porous structure improves the ionic and electronic conductivity, resulting in a substantial enhancement in rate capability. Even at high current densities of 2 and 5 mA cm^-2, the 3D-printed LFP cells with LCN deliver the areal capacities of 8.75 and 3.50 mAh cm^-2, respectively. And after 100 cycles at 0.3 mA cm^-2, it remains at a high capacity of 6.98 mAh cm^-2, breaking the limitation of ion transport in thick electrodes. This work provides a strategy in addressing the wettability challenges of thick electrodes, opening another way for the development of high-energy/power-density energy storage systems.