Lithium-ion batteries (LIBs) are essential energy storage solutions that support advancements in modern electronic applications. However, the inherent flammability of liquid electrolytes significantly increases fire safety risks, posing a significant barrier to their wider adoption. Although substantial research efforts have focused on developing non-flammable or flame-retardant electrolytes, the simultaneous attainment of optimal cell-level safety and excellent electrochemical performance remains a complex challenge that requires further exploration. A deep and comprehensive understanding of safer electrolyte designs is essential for the development of more effective strategies aimed at improving LIB safety. This review critically examines the latest advancements in non-flammable and flame-retardant electrolytes, covering areas such as molecular engineering, functional additive incorporation, and complex modifications to solvation structures. Furthermore, we provide valuable insights into future research directions, emphasizing the urgent need for the creation of multi-functional electrolyte solutions that seamlessly integrate safety, stability, and superior electrochemical performance.