Portable electronic devices (PEDs) are promising information‐exchange platforms for real‐time responses. Their performance is becoming more and more sensitive to energy consumption. Rechargeable batteries are the primary energy source of PEDs and hold the key to guarantee their desired performance stability. With the remarkable progress in battery technologies, multifunctional PEDs have constantly been emerging to meet the requests of our daily life conveniently. The ongoing surge in demand for high‐performance PEDs inspires the relentless pursuit of even more powerful rechargeable battery systems in turn. In this review, we present how battery technologies contribute to the fast rise of PEDs in the last decades. First, a comprehensive overview of historical advances in PEDs is outlined. Next, four types of representative rechargeable batteries and their impacts on the practical development of PEDs are described comprehensively. The development trends toward a new generation of batteries and the future research focuses are also presented.

Exceptionally large surface area and well-defined nanostructure are both critical in the field of nanoporous carbons for challenging energy and environmental issues. The pursuit of ultrahigh surface area while maintaining definite nanostructure remains a formidable challenge because extensive creation of pores will undoubtedly give rise to the damage of nanostructures, especially below 100 nm. Here we report that high surface area of up to 3,022 m² g⁻¹ can be achieved for hollow carbon nanospheres with an outer diameter of 69 nm by a simple carbonization procedure with carefully selected carbon precursors and carbonization conditions. The tailor-made pore structure of hollow carbon nanospheres enables target-oriented applications, as exemplified by their enhanced adsorption capability towards organic vapours, and electrochemical performances as electrodes for supercapacitors and sulphur host materials for lithium–sulphur batteries. The facile approach may open the doors for preparation of highly porous carbons with desired nanostructure for numerous applications.

In this paper, we report the electrochemical capacitive properties of polystyrene-based hierarchical porous carbon (PS-HPC) for supercapacitors. Compared to many porous carbons such as a commercially available activated carbon and an ordered mesoporous carbon, PS-HPC has a unique three-dimensionally (3D) interconnected micro-, meso- and macroporous network and thus exhibits faster ion transport behavior and a larger utilization of surface area in electric double layer capacitors. The 3D interconnected meso- and macroporous network originates respectively from the compact and loose aggregation of crosslinked polystyrene-based carbon nanoparticles, and is able to facilitate rapid ion transfer/diffusion rates. Furthermore, PS-HPC's micropores exist from the 3D interconnected network inside these crosslinked polystyrene-based carbon nanoparticles, thus giving an exceptional electrochemically accessible surface area for charge accumulation. As a result, the capacitance retention ratio and capacitance per surface area of PS-HPC at a high sweep rate of 200 mV s⁻¹ are as high as 84% and 28.7 μF cm⁻², respectively. These encouraging results demonstrate the promising application of PS-HPC for high performance supercapacitors.

The development of an effective route to high-performance carbonaceous electrode materials derived from low-cost biomass is critical but remains challenging for supercapacitors. Here we propose a new and cost-effective way to produce chitosan-based hierarchical porous carbons by the union of hydrothermal carbonization and chemical activation. The key to this preparation strategy is the utilization of acetic acid as an additive for hydrothermal carbonization, which not only favors the construction of a conducive environment for accessibility of activator KOH, but also leads to the formation of a rigid semi-carbonized framework substrate for generating an ultrahighly porous structure. Thus, our synthetic approach allows for a lower amount of activation agent and lower heating temperature when compared with normal chemical activation techniques, providing a more efficient way to produce ultrahigh-surface-area carbon materials. The as-prepared hierarchical porous carbon possesses a unique honeycomb-like framework and the highest BET surface area of 3532 m² g⁻¹ among all the carbon materials derived from chitosan. The combination of the hierarchical pore structure for rapid ion diffusion and the ultrahigh surface area for sufficient electrochemically active sites significantly improves the material's capacitive behaviors. An unusually high capacitance of 455 F g⁻¹, an excellent cycling stability with 99% capacity retention over 20 000 cycles in KOH aqueous electrolyte, and a high energy density of 20.6 W h kg⁻¹ at a power density of 226.8 W kg⁻¹ in 1.8 V Na₂SO₄ aqueous supercapacitors have been obtained, demonstrating that the chitosan-based hierarchical porous carbons developed here are very attractive for application in supercapacitors.