High energy density quasi-solid-state lithium-ion batteries: dry electrode process and gel polymer electrolyte securing 4.5 V stable high-loading cathode technology

Using high-loading thick electrodes prepared by dry electrode process is an effective way for higher energy density Lithium-ion batteries(LIBs). The integration of gel polymer electrolytes (GPEs) with traditional slurry-cast thick electrodes remains fundamentally challenged by interfacial incompatibility, sluggish ion transport kinetics, mechanical stress accumulation, and parasitic side reactions from residual solvents, leading to performance decay. This study presents a novel strategy for constructing stable 4.5 V high-loading lithium-ion batteries through the synergistic integration of dry electrode and in-situ polymerized GPEs. The inherent solvent-free nature of the dry process avoids the parasitic side reactions associated with residual solvents. Consequently, the Dry electrode-LiNi 0.8 Mn 0.1 Co 0.1 O 2 (DE-NCM811) fabricated via polytetrafluoroethylene (PTFE) fibrillation-calendering demonstrates seamless interfacial compatibility when coupled with a fluorinated grafted gel polymer electrolyte formed by in-situ free-radical polymerization. Galvanostatic intermittent titration technique (GITT) and electrochemical impedance spectroscopy (EIS) evaluations confirm superior Li + diffusion kinetics and interfacial stability in the DE-NCM811|GPE|Li. Comparative electrochemical analysis reveals the superior performance of the DE-NCM811|GPE|Li, demonstrating 83.89 % capacity retention after 120 cycles in the voltage range of 3–4.5 V at 0.2 C, enhanced rate capability of 217.25 mAh g −1 at 0.1 C, stable cycling performance at high loadings of 75 mg cm −2 (80.18 % capacity retention) after 70 cycles.