This review provides the most recent advances in wearable energy sources based on 2D materials, and highlights the crucial roles 2D materials play in the wearable energy sources.

Used as a bare active material or component in hybrids, graphene has been the subject of numerous studies in recent years. Indeed, from the first report that appeared in late July 2008, almost 1600 papers were published as of the end 2015 that investigated the properties of graphene as an anode material for lithium‐ion batteries. Although an impressive amount of data has been collected, a real advance in the field still seems to be missing. In this framework, attention is focused on the most prominent research efforts in this field with the aim of identifying the causes of such relentless progression through an insightful and critical evaluation of the lithium‐ion storage performances (i.e., 1^st cycle irreversible capacity, specific gravimetric and volumetric capacities, average delithiation voltage profile, rate capability and stability upon cycling). The “graphene fever” has certainly provided a number of fundamental studies unveiling the electrochemical properties of this “wonder” material. However, analysis of the published literature also highlights a loss of focus from the final application. Hype‐driven claims, not fully appropriate metrics, and negligence of key parameters are probably some of the factors still hindering the application of graphene in commercial batteries.

Graphite was electrochemically exfoliated in mixtures of room temperature ionic liquids and deionized water containing lithium salts to produce functionalized graphenes and such an electrochemical exfoliation technique can be directly used in making primary battery electrodes with significantly enhanced specific energy capacity.

Solar energy is a renewable and abundant energy source that has myriad potential applications to be tapped. Energy storage devices often present diminishing performance at lower temperatures, and sometimes they even fail during cold weather; therefore, a renewable technology to spur such sluggish performance not only is important for a sustainable future but also may inspire new-concept devices such as ignition sensors. Here, under solar illumination, the capacitance, energy density and power density of supercapacitors are all largely enhanced owing to the photothermal effect. The supercapacitors employ three-dimensional hierarchical graphene as the electrodes, and show an absorption of >92.88% over the entire solar spectrum, a response time of <200 s, and a surface temperature change of ∼39 °C under 1 solar illumination (1 kW m⁻²). Under 1 solar illumination, the capacitance of the pseudocapacitor increases by ∼1.5 times, and the capacitance of the electric double-layer capacitor increases by ∼3.7 times. The mechanism is quantitatively analyzed and discussed. This work provides new insights into the applications of solar energy and offers new design options for the development of energy storage devices.