Black phosphorus (BP) is rediscovered as a 2D layered material. Since its first isolation in 2014, 2D BP has triggered tremendous interest in the fields of condensed matter physics, chemistry, and materials science. Given its unique puckered monolayer geometry, 2D BP displays many unprecedented properties and is being explored for use in numerous applications. The flexibility, large surface area, and good electric conductivity of 2D BP make it a promising electrode material for electrochemical energy storage devices (EESDs). Here, the experimental and theoretical progress of 2D BP is presented on the basis of its preparation methods. The structural and physiochemical properties, air instability, passivation, and EESD applications of 2D BP are discussed systemically. Specifically, the latest research findings on utilizing 2D BP in EESDs, such as lithium‐ion batteries, supercapacitors, and emerging technologies (lithium–sulfur batteries, magnesium‐ion batteries, and sodium‐ion batteries), are summarized. On the basis of the current progress, a few personal perspectives on the existing challenges and future research directions in this developing field are provided.

A harmonized three-component composite system which preserves the characteristics of individual components is of interest in the field of energy storage. Here, we present a graphene-encapsulated MXene Ti 2 CT x @ polyaniline composite (GMP) material realized in a systematically stable configuration with different ternary nanomaterials for supercapacitor electrodes. Due to the different ζpotentials in a high-pH solution, chemically converted graphene (negatively charged) is thoroughly unfolded to allow full encapsulation, but the MXene Ti 2 CT x @polyaniline composite with a low positive ζ-potential is easily attracted toward a counter-charged substance. The obtained GMP electrode exhibits improved cycling stability and better electrochemical performance owing to the use of mechanically robust and chemically inert graphene and the densely intercalated conductive polyaniline between the multilayer MXenes. The GMP electrode has a high gravimetric capacitance of 635 F g −1 (volumetric capacitance of 1143 F cm −3 ) at a current density of 1 A g −1 with excellent cycling stability of 97.54% after 10 000 cycles. Furthermore, the asymmetric pouch-type supercapacitor assembled using the GMP as a positive electrode and graphene as a negative electrode yields a high energy density of 42.3 Wh kg −1 at a power density of 950 W kg −1 and remarkable cycling stability (94.25% after 10 000 cycles at 10 A g −1 ).

The development of SiO x electrode with high mass loading, which is an important prerequisite for practical lithium-ion batteries, remains an arduous challenge by using existing binders. Herein, we propose a three-in-one design strategy for binder systems in allintegrated SiO x electrodes. "Hard" poly(furfuryl alcohol) (PFA) and "soft" thermoplastic polyurethane (TPU) are interweaved into 3D conformation to confine SiO x particles via in-situ polymerization. In the electrode system, PFA works as a framework and TPU servers as a buffer, and H-bonding interactions are formed between the components. Benefiting from the three-pronged collaborative strategy, PFA-TPU/SiO x electrode exhibits an areal capacity of 2.4 mAh cm −2 at a high mass loading of >3.0 mg cm −2 after 100 cycles. Such a binder system is also extended to other potential metal oxides anode with high mass loading, e.g., Fe 2 O 3 and SnO 2 , thus shedding light on rational design of functional polymer binders for high-areal-capacity electrodes.

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