1. R. Thangavel, and Y.-S. Lee, Manufacturing Method of Na-ion Hybrid Capacitor Electrode & Capacitor made by the same. Korean patent, Patent No: 1017834350

2. Y.-S. Lee, and R. Thangavel, Sodium Hybrid Capacitor and Preparation Method Thereof. Korean patent, Patent No: 102066998000, Reg. Date: 10.01.2020 000, Reg. Date: 25.09.2017