Here, we present a combined experimental and molecular dynamical (MD) simulation study to demonstrate that the pseudocapacitive charge storage in layered manganese oxide can be enhanced by tuning the interlayer region. Interlayer expanded layered manganese oxide (10 Å interlayer spacing) was synthesized by metal (Mg2+, Ca+2) intercalation where, originally present Na+ ions were replaced by an ion exchange reaction. Interlayer modified layered manganese oxide exhibited an improved specific capacitance of 290 Fg-1 contrary to pristine layered manganese oxide (7 Å interlayer spacing). However, the specific capacitance of interlayer expanded layered manganese oxide reduced to 155 Fg-1 when Na+ ion containing electrolyte was used. Ex-situ x-ray diffraction suggested that Mg ions in the electrolyte stabilize the interlayer expanded structure while Na+ ion seems to modify interlayer expanded layered manganese oxide back to the regular layered manganese oxide. The energetics of this transformation and enhanced pesudocapacitive behaviour in modified layered manganese oxide was studied using MD simulations.

Interlayer expanded layered manganese oxide for enhanced pseudocapacitive electrochemical energy storage

254th National Meeting (2017)

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