The innovation engine for new materials

Katherine Danks


University of Oxford


Materials Science


Megan Butala

Faculty Sponsor(s): 

Ram Seshadri

Faculty Sponsor's Department: 

Materials Research Laboratory

Project Title: 

Porous Manganese (II) Oxide for Use as a High Capacity Anode

Project Description: 

Batteries used in high power applications, such as electric cars, operate by a mechanism known as intercalation, which has inherent capacity limitations. This can be improved upon by the use of materials that operate by an alternative mechanism known as conversion. MnO powder has been previously investigated as a conversion anode, motivated by the high capacity and small voltage hysteresis of MnO relative to other conversion materials. Here we investigate how the morphology of the electrode powder affects the reversible capacity and the voltage hysteresis of the electrode. Porous MnO powder with pores between 15nm and 40nm in length is synthesised by the reductive heating of Mn3O4 at 475°C for 6 hours. Bulk and porous MnO powders are examined using X-ray diffraction and scanning electron microscopy to characterise their compositions and morphology. Powders are then cast into electrodes for testing in coin cells that undergo electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic cycling with potential limitation. Due to the short diffusion lengths and increased surface area of the porous MnO, we expect that lithium transport will be improved, leading to decreased hysteresis and increased capacity. If these results are observed, porous MnO may be a promising anode material for use in high capacity batteries. Future work will consider how different pore sizes and morphologies affect the electrochemical performance of conversion electrodes as well as methods for efficiently synthesising such materials.