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We report a general emulsion approach to protrude a lobe by swelling the polymer core from a core−shell structure, achieving anisotropic Janus composite particles with tunable chemistry, shape, size, and size ratio of the two parts thus Janus balance. Oil-in-water emulsion is employed to swell a polymer core through the crack open hole within the shell, and the core protrusion is restricted in the particle/oil confined compartments enveloped with surfactant. When monomers are used as the oil solvents, cross-linking can strengthen the polymer lobe to tolerate against organic solvents. By tuning polymerization time and monomer/particle weight ratio, the size ratio of the polymer/inorganic parts thus Janus balance of the composite particles is continuously tunable across from more hydrophilic to more lipophilic. The robust anisotropic particles with tunable Janus balance can be further used as solid surfactants to tune microstructure of emulsions.

Abstract2D ion‐intercalated metal oxides are emerging promising new electrodes for supercapacitors because of their unique layered structure as well as distinctive electronic properties. To facilitate their application, fundamental study of the charge storage mechanism is required. Herein, it is demonstrated that the application of in situ Raman spectroscopy and electrochemical quartz crystal microbalance with dissipation monitoring (EQCM‐D), provides a sufficient basis to elucidate the charge storage mechanism in a typical 2D cation‐intercalated manganese oxide (Na0.55Mn2O4·1.5H2O, abbreviated as NMO) in neutral and alkaline aqueous electrolytes. The results reveal that in neutral Na2SO4 electrolytes, NMO mainly displays a surface‐controlled pseudocapacitive behavior in the low potential region (0–0.8 V), but when the potential is higher than 0.8 V, an intercalation pseudocapacitive behavior becomes dominant. By contrast, NMO shows a battery‐like behavior associated with OH− ions in alkaline NaOH electrolyte. This study verifies that the charge storage mechanism of NMO strongly depends on the type of electrolyte, and even in the same electrolyte, different charging behaviors are revealed in different potential ranges which should be carefully taken into account when optimizing the use of the electrode materials in practical energy‐storage devices.

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Lithium ion hybrid capacitors (LIHCs) have high power density and high energy density. One of the biggest problems in LIHCs is the kinetics mismatch of a battery-type anode and capacitive...

The operation of electrochemical energy storage (EES) devices at low temperatures as normal as at room temperature is of great significance for their lowtemperature environment application. However, such operation is plagued by the sluggish ions transport kinetics, which leads to the severe capacity decay or even failure of devices at low-temperature conditions. In this review, the difficulties of ions transport in electrolyte, electrolyte/electrode interface, and electrode material at low temperatures are discussed in depth, and the reported strategies to solve the corresponding problems are surveyed subsequently. Finally, the views on how to build high-performance low-temperatureavailable EES devices as well as their development directions are put forward.

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