Multifunctional Carbon Dots for High‐Performance Polymer Electrolytes

The pursuit of high‐energy‐density and safe rechargeable batteries has driven intense research into solid‐state and quasi‐solid‐state electrolytes, among which polymer electrolytes stand out for their flexibility, processability, and electrode compatibility. However, their practical application is critically hindered by low room‐temperature ionic conductivity, poor Li + selectivity, insufficient mechanical strength, and unstable electrode/electrolyte interfaces. Carbon dots (CDs), with ultrasmall dimensions, tailorable surface chemistry, and versatile processability, have recently emerged as a class of multifunctional nanoscale regulators to address these challenges. This mini review systematically discusses the underlying mechanisms by which CDs enhance polymer electrolyte performance, including polymer‐chain regulation, Li + coordination modulation, continuous ion‐transport pathway construction, mechanical network reinforcement, and interfacial chemistry stabilization. The structure‐property‐performance relationships are emphasized. Finally, key challenges and future directions toward practical solid‐state lithium batteries are outlined.