Charge Storage Mechanism Analysis of Sustainable Hybrid Redox-Active Capacitors Using Either Liquid or Solid-State Electrolytes

Electrochemical energy storage is getting more hype in the fight against climate change. Nevertheless, there is still a huge emphasis on lithium chemistry in this market, which poses extra strain over natural resources. In this work, we are proposing a promising alternative using all organic active materials, which can open up an avenue toward more sustainable design of energy storage. Using catechol as active materials with high theoretical capacity of 240 mAh·g–1, we showed that we can outperform most electric double layer capacitors and pseudocapacitors with maximum energy and power densities of 95 Wh·kg–1 and 8.9 Wh·kg–1. Also, careful selection and optimization of the electrolyte system can improve the performance of the device. Therefore, we carefully analyzed the charge storage mechanisms of the devices using both solid-state and liquid electrolytes of choice, showing further the importance of the electrolyte design in the performance of the device.