In-situ diagnosis appears to be one of the essential methods for gaining insights as how an electrode material failure, therefore feeding back for designing and creating new materials with enhanced battery performances. In this presentation, I will highlight recent progress on ex-situ, in-situ and operando S/TEM for probing into the structural and chemical evolution of energy storage materials. Both ex-situ and in-situ high resolution imaging enables direct observation of structural evolution, phase transformation and their correlation with mass, charge and electron transport, providing insights as how active materials failure during the cyclic charging and discharging of a battery. In particular, I will broadly cover the frontier of the current understanding of the fading mechanism of layer structured cathode. Subsequently, I will discuss some recent breakthrough experiments/observations for correlating the structural/chemical evolution with the electrochemical properties of this category of materials and their implications. In perspective, my presentation will target to stimulate this field of research to re-check what has been understood and what need to be done to tackle the technical challenges facing the application of the layer structured cathode materials.