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Widespread integration of carbon‐based membranes into prevailing fields like energy storage and material engineering is thwarted by a lack of functionality, customization, and compatibility, making the development of such carbon‐based membranes urgency yet challenging. Herein, a "graphene bubble bridging" strategy is adopted to fabricate the multifunctional carbon fiber membrane, in which graphene bubbles with optimized assembling not only endow the carbon fiber with superior flexibility and integrity by embedded bridging function, but also enhance the fast electron transport capability and electrolyte wettability. Few‐layer MoSSe nanosheets with expanded interlayer spacing as a typical energy storage material contribute to plentiful ion intercalation/deintercalation that can be well buffered within the robust fibers. The interlaced carbon fibers enable a self‐supporting framework that ensures good conductivity and mechanical stability as well. Such functional, customized, and compatible membranes with synergies can boost the attributes of advanced K+ storage devices, such as flexible K‐ion capacitors and K‐based dual‐ion batteries. This work can afford new insights for designing flexible electrode in the energy storage field, as well as various types of conformations that can bring more opportunities on developing flexible functional membranes for other fields (e.g., catalysts, electromagnetic shielding). [ABSTRACT FROM AUTHOR]

[Display omitted] Potassium-based energy storage has emerged as a promising alternative for advanced energy storage systems, driven by the abundance of potassium, fast ion migration, and low standard electrode potential. Hybrid capacitors, which combine the desirable characteristics of batteries and supercapacitors, offer a compelling solution for efficient energy storage. In this study, we present the development of versatile composite materials, specifically potassium vanadium fluorophosphate (KVPO 4 F) composites, utilizing a sol–gel method. These composites enable tunable potassium storage and charge transport kinetics within regulated voltage windows, serving as both cathode and anode materials. The anode composite, composed of KVPO 4 F and hierarchical porous carbon (HPC), exhibited exceptional stability over 400 cycles within a low-voltage window. On the other hand, the cathode composite, consisting of battery-like KVPO 4 F and physisorption activated carbon (AC), demonstrated great potential as a cathode material, striking a balance between specific energy and cycle life within a regulated high-voltage window. By integrating KVPO 4 F/C as the anode and KVPO 4 F/AC as the cathode, we successfully created potassium-ion hybrid capacitors (PIHCs) that showcased an impressive capacity retention of 83% after 10,000 cycles within a high voltage window of 0.5–4.3 V. Furthermore, to explore the application of these materials in miniaturized energy storage, we fabricated potassium-ion micro hybrid capacitors (PIMHCs) with interdigitated electrodes. These devices exhibited a high areal energy density of 18.8 μWh cm−2 at a power density of 111.6 μW cm−2, indicating their potential for compact energy storage systems. The results of this study demonstrate the versatility and efficacy of the developed KVPO4F composite materials, highlighting their potential for future advancements in potassium-based energy storage technologies. [ABSTRACT FROM AUTHOR]

Confining active nanoparticles in hierarchically porous carbon to construct intercalation and conversion coupling mechanisms is one promising way to achieve high-performance energy storage electrodes. However, this carbon with fragile mesoporous walls always suffer from fragmentation during the ion intercalation/deintercalation process, which would lead to the blocking of the whole electron transport network and the detachment of active particles, resulting in the capacity attenuation. Herein, reduced graphene oxide (rGO) bubbles are successfully introduced into N-doped hierarchically porous carbon (rGO-NPC) confined conversion-type nanoparticles to enhance their electrochemical performance. The rGO bubbles not only can afford an uninterrupted electron transport network, accelerating the reaction kinetics of active nanoparticles, and thus improving the capacity, but also can buffer the volume change of porous carbon, maintaining the integrity of electrode materials, and thereby, enhancing the cycling performance. With FeS 2 as an example, when employed in Na/K-ion capacitors (SICs/KICs), the FeS 2 @rGO-NPC electrode can reach a high maximum energy/power density (110 Wh kg−1/20935 W kg−1 for SICs and 134 Wh kg−1/17973 W kg−1 for KICs) with a great cycling performance (82%/91% of capacitance retentions at 2 A g−1 after 10000/15000 cycles for SICs/KICs). This work indicates a promising way for designing porous carbon-based anodes with high-performance for alkali metal ions storage. [Display omitted] [ABSTRACT FROM AUTHOR]

The selenium (Se) electrochemistry plays a critical role in developing new generation electrochemical energy storage systems beyond the ever-dominating lithium based era. However, fast kinetics and stable Se electrochemistry still remain great challenges, particularly involving K+ reaction instead of Li+. Herein, we report a facile carbon host using pore structure regulation strategy, in which the abundant micropores provide large specific surface area and pore volume that can physically confine and accommodate the small molecular Se. These micropores not only boost the fast reaction kinetics of small molecular Se with K+, but also can restrain the shuttle effect of polyselenides effectively during the reversible reaction. The ordered and interconnected macropores and mesopores can offer rapid mass transfer channels, together with the chemical adsorption from the N-doping, synergistically improving the charger transfer efficiency and reversible stability. The Se/nitrogen-doped macro-/meso-/microporous carbon (Se@NM3C) delivers large specific capacity of 728 mA h g−1 (0.05C), remarkable rate performance, and superior cycling stability. A novel potassium ion (K-ion) capacitors based on this Se–K electrochemistry (Se–KICs) can achieve high energy/power densities and great long-term service life (86% after 10,000 cycles at 2 A g−1). This work unveils insights into chalcogen based electrochemistry for high performance electrochemical energy storage systems. Fast kinetics and stable Se electrochemistry remain great challenges, particularly involving K+ reaction instead of Li+. This manuscript reports a delicate carbon host pore structure regulation strategy, which enables fast and super stable Se–K electrochemistry through precisely physical and chemical confinement. Based upon this, the assembled novel K-ion capacitors (Se–KICs) display high energy/power densities and great long term service life. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Mn 3 O 4 @TiO 2 nanocomposite was successfully prepared from a dual-template method. • Mn 3 O 4 @TiO 2 nanocomposite possesses 3D ordered hierarchically porous structure and heterostructured Mn 3 O 4 /TiO 2 interfaces. • Mn 3 O 4 @TiO 2 shows high energy/power densities and good cycle durability in SICs. Sodium-ion hybrid capacitors (SICs) are recognized as a promising new energy storage devices. The design of anodes with high rates to balance the fast desorption/adsorption process in cathode is a key way to construct desirable SICs. Herein, Mn 3 O 4 nanoparticles are in situ embedded in TiO 2 to form Mn 3 O 4 @TiO 2 nanocomposite as anode for SICs. The prepared Mn 3 O 4 @TiO 2 nanocomposite shows hierarchically porous structure with macropores and mesopores. The Mn 3 O 4 content in the composites can be adjusted to achieve the balance between the hierarchically porous structure and heterostructured Mn 3 O 4 /TiO 2 interfaces. The optimized Mn 3 O 4 @TiO 2 with ∼30 wt% Mn 3 O 4 achieves this balance, delivering a large discharge capacity of 247.8 mAh g−1 at 1 A g−1 after 1000 cycles in SIBs. The assembled SICs by using Mn 3 O 4 @TiO 2 -2 as anode and commercial activated carbon as cathode can achieve a high energy and power densities of 106.5 Wh kg−1 and 10140.5 W kg−1, respectively, and an extended cycle life of 92.8 % retention after 5000 cycles. The good Na-ion storage performance mainly arises from the macropores that can provide rapid mass transfer channels, the mesopores that can offer high specific surface areas and highly dispersed Mn 3 O 4 nanoparticles and abundant Mn 3 O 4 /TiO 2 interfaces that can afford a lot of active sites. [ABSTRACT FROM AUTHOR]

One dimensional (1D) fiber-shaped energy storage device demonstrates a great potential for the future power source textiles. However, delivering high energy/power densities and long cycle life is still the crucially electrochemical themes to meet the ever-stringent demands. Herein, we report a novel non-aqueous fiber-shaped potassium ion capacitors (PICs), in which 1D K 2 Ti 6 O 13 nanobelts (KTO) interweaved with three-dimensional (3D) porous carbon framework was synthesized as anode materials. The low specific capacity and sluggish reaction kinetics of the bare KTO is boosted by the 3D porous carbon framework. Its hierarchical porosity and 3D structure impede the aggregation of the KTO, and favor the permeation of potassium ions in electrolyte. Its graphitic carbon improves the electrical conductivity of the KTO. Meanwhile, it also offers a suitable potassium ion storage capacity. These features enable KTO@3D-C with high specific capacity and rate performance. A single non-aqueous fiber-shaped PICs with a high working voltage up to 3.5 V can lead to maximum areal and volumetric energy densities of 12.1 μWh cm−2 and 1.9 m Wh cm−3, indicating apparent energy advantages over the ones with aqueous electrolyte and symmetric configuration. Our integratable and robust fiber-shaped PICs prototype demonstrates a great potential for future power source textiles. [Display omitted] • Fiber shaped potassium ion capacitor is designed. • High areal and volumetric energy densities are delivered. • 1D K 2 Ti 6 O 13 nanobelts interweaved with 3D porous carbon framework act as anode. • Low specific capacity and sluggish reaction kinetics of KTO is boosted. [ABSTRACT FROM AUTHOR]

MoSe 2 presents a prospect in sodium-ion capacitors (SICs) and lithium-ion capacitors (LICs), which are considered as promising new energy systems because they possess the merits of both batteries and supercapacitors. In this work, we develop a flexible and free-standing MoSe 2 /MXene film with sandwich structure as an anode for SICs and LICs. The highly conductive MXene sheets can boost the electrochemical activity of MoSe 2 nanoparticles. Meanwhile, the MoSe 2 nanoparticles can also enlarge the interlayer spacing of MXene film, facilitating the permeation of electrolyte and eventually leading to fast reaction kinetics of MoSe 2. The sandwich structure can effectively limit the loss of intermediate products generated during the insertion/extraction reactions of MoSe 2 , giving rise to a durable cycle performance. The MoSe 2 /MXene film with an optimized mass ratio exhibits much improved Li/Na storage performances as compared with the pristine MoSe 2 , particular the long term cyclic stability. SICs and LICs could deliver high energy/power densities (Max 110.1 Wh kg−1/4764.7 W kg−1 and 84.9 Wh kg−1/3288.3 W kg−1, respectively), as well as long lifespans, demonstrating the prospective of such MXene/MoSe 2 film electrode towards alkali metal ion capacitors. Assembled flexible SICs/LICs prototypes further prove the potential application for the future flexible energy storage devices. MoSe 2 /MXene film electrode with a sandwich structure exhibits a great electrochemical performance for SICs and LICs. Image 1 • Flexible and free-standing MoSe 2 /MXene films with sandwich structure are prepared. • The cyclic performance of MoSe 2 is much improved by this composite film way. • The probed mechanism gives insights into the ion storage performance. • MoSe 2 /MXene film exhibits a great performance as the anode for SICs and LICs. [ABSTRACT FROM AUTHOR]