Battery separators are thin materials used in batteries to keep the positive and negative electrodes apart. They prevent short circuits by allowing ions to pass through while blocking direct contact between the electrodes. This separation is crucial for the safe and efficient operation of batteries, including those found in electric vehicles and portable electronics. These separators are typically made from materials like polyethylene or polypropylene, which are lightweight and chemically stable. Their design can influence a battery's performance, including its capacity, lifespan, and charging speed. Properly functioning separators contribute to the overall safety and efficiency of battery systems.