'Energy materials' encompass a wide range of technologies, ranging from thermoelectrics to fuel cells, batteries, photovoltaics and magnetocalorics, among others. Many of these energy materials are developed as multi-component solid state devices and these devices inherently possess a number of electrochemically active interfaces. It is these interfaces, e.g. solid/solid, liquid/solid or gas/solid, that control the function of the device, and are typically the source of degradation. Many current techniques used to analyse these devices and their components rely on idealised systems in high vacuum environments to gain information on the near surface chemistry. This necessitates the use of post-mortem operation analysis and clearly represents a significant mismatch from the conditions under which devices operate. Increasingly it is acknowledged that in-operando measurements are required, but that the measurements are themselves difficult and demanding. It is our intention to develop expertise with in-operando characterisation of energy materials. This will build on our existing expertise and capability in surface analysis and in-situ measurements. As an example, a fuel cell operating at 823K will be subjected to temperature gradients, cation segregation, potential gradients, poisoning and chemical changes induced by these conditions, all of which are inter-related, but separating the individual contributions has so far proved impossible. Similar issues involving the interface and surface chemistry of solid state batteries, permeation membranes and co-electrolysers will also be addressed using these techniques. By developing in-operando correlative characterisation we aim to deconvolute these processes and provide detailed mechanistic understating of the critical processes in a range of energy systems.