Integration of Porous High‐Loading Electrode and Gel Polymer Electrolyte for High‐Performance Quasi‐Solid‐State Battery

Abstract The practical applications of lithium‐ion batteries (LIBs) are challenged by safety concerns using liquid electrolytes (LEs). The gel polymer electrolytes (GPEs) are considered as a promising candidate to solve this safety issue. In addition, using high‐mass loading electrodes is essential to achieve high energy density. However, poor interfacial contact between electrode and electrolyte remains a challenging issue, particularly for the high‐mass‐loading electrode. Here, porous channels are constructed in electrodes with high active material loading using the melamine formaldehyde sponge, and then the GPE is penetrated into porous channels of electrodes through an in‐situ thermal induced polymerization. The porous electrode structure with sufficient surface area improves electrolyte percolation and fast ion diffusion kinetics, which enables a uniform distribution of Li‐ion flux and effectively homogenizes the local current density to realize uniform Li deposition. The half cells and anode‐free full cells using the integration of porous electrodes and in‐situ polymerized GPEs exhibit excellent discharge capacity and cycle stability. This integration method is applicable for fabricating batteries with high energy density and safety.