MnO₂-deposited lignin-based carbon nanofiber mats for application as electrodes in symmetric pseudocapacitors

Low-cost, high-performance electrodes are highly attractive for practical supercapacitor applications. MnO₂-deposited carbon nanofiber mats (MnO₂-CNFMs) are prepared for use as binder-free supercapacitor electrodes. MnO₂ is deposited on the mats in situ by hydrothermally decomposing aqueous KMnO₄, leading to the formation of nanocrystals of MnO₂. The MnO₂-CNFM electrode produced with 38.0μmol KMnO₄ (this electrode) shows a high specific capacitance of ~171.6F·g^-1 at a scan rate of 5mV·s^-1. Moreover, a symmetric supercapacitor with the electrode exhibits a specific capacitance of 67.0F·g^-1, an energy density of 6.0Wh·kg^-1 and a power density of 160W·kg^-1 at a special current of 0.1A·g^-1. Further, the symmetric supercapacitor displays excellent cycling stability, retains approximately 99% of the capacitance after 1000cycles. The simplicity and ease of preparation of the MnO₂-CNFMs as well as their suitability for use in coin-type supercapacitor cells make them ideal for application in cost-effective and high-performance electrodes for supercapacitors.