Template-derived high surface area λ-MnO2 for supercapacitor applications

The synthesis of lambda-manganese oxide (lambda-MnO2) with a developed porosity and an ordered and interconnected pore structure used as supercapacitor electrode is reported for the first time in the present study. A spinel-type LiMn2O4 material was first prepared by hard-templating pathway using KIT-6 mesoporous silica as a template and metal nitrates as precursors, which was subsequently acid treated leading to lambda-MnO2 material. The materials exhibit high surface area (up to 150 m(2) g(-1)), defined pore size distribution with three-dimensional interconnected pores, and crystalline pore walls. The material textural properties as well as the morphologies vary considerably with the synthetic conditions. The as-synthesized porous lambda-MnO2 materials exhibit a noticeably better performance (120 F g(-1)) at high constant currents (1 A g(-1)) than commercial derived lambda-MnO2 (11 F g(-1)). The extended surface area and the porous and three-dimensional interconnected structures along with the specific morphology significantly enhance the lithium diffusion through the particles and allow for a more effective use of this pseudocapacitive material as an electrode in supercapacitor.