API Reference IconPool: https://sapui5.hana.ondemand.com/sdk/#/api/sap.ui.core.IconPool
In my case I used a custom formatter and the getIconForMimeType() function from the IconPool to get the required Icons for my list items.
myView.xml
icon="{path: 'mimeType', formatter: '.formatter.getIconForMimeType'}">
formatter.js
getIconForMimeType: function(sMimeType) {
return sap.ui.core.IconPool.getIconForMimeType(sMimeType)
}