Sodium-ion batteries operating at room temperature have emerged as a generation of energy storage devices to replace lithium-ion batteries; however, they are limited by a lack of anode materials with both an adequate lifespan and excellent rate capability. To address this issue, we developed Nb 2 CT x MXene-framework MoS 2 nanosheets coated with carbon (Nb 2 CT x @MoS 2 @C) and constructed a robust threedimensional cross-linked structure. In such a design, highly conductive Nb 2 CT x MXene nanosheets prevent the restacking of MoS 2 sheets and provide efficient channels for charge transfer and diffusion. Additionally, the hierarchical carbon coating has a certain level of volume elasticity and excellent electrical conductivity to guarantee the intercalation of sodium ions, facilitating both fast kinetics and long-term stability. As a result, the Nb 2 CT x @MoS 2 @C anode delivers an ultrahigh reversible capacity of 530 mA h g −1 at 0.1 A g −1 after 200 cycles and very long cycling stability with a capacity of 403 mA h g −1 and only 0.01% degradation per cycle for 2000 cycles at 1.0 A g −1 . Moreover, this anode has an outstanding capacity retention rate of approximately 88.4% from 0.1 to 1 A g −1 in regard to rate performance. Most importantly, the Nb 2 CT x @MoS 2 @C anode can realize a quick charge and discharge at current densities of 20 or even 40 A g −1 with capacities of 340 and 260 mAh g −1 , respectively, which will increase the number of practical applications for sodium-ion batteries. KEYWORDS: Nb 2 CT x @MoS 2 @C, Nb 2 CT x MXene, 3D network, sodium-ion batteries, high rate performance, high capacity

Accurate and continuous detection of physiological signals without the need for an external power supply is a key technology for realizing wearable electronics as next‐generation biomedical devices. Herein, it is shown that a MXene/black phosphorus (BP)‐based self‐powered smart sensor system can be designed by integrating a flexible pressure sensor with direct‐laser‐writing micro‐supercapacitors and solar cells. Using a layer‐by‐layer (LbL) self‐assembly process to form a periodic interleaving MXene/BP lamellar structure results in a high energy‐storage capacity in a direct‐laser‐writing micro‐supercapacitor to drive the operation of sensors and compensate the intermittency of light illumination. Meanwhile, with MXene/BP as the sensitive layer in a flexible pressure sensor, the pressure sensitivity of the device can be improved to 77.61 kPa–1 at an optimized elastic modulus of 0.45 MPa. Furthermore, the smart sensor system with fast response time (10.9 ms) shows a real‐time detection capability for the state of the human heart under physiological conditions. It is believed that the proposed study based on the design and integration of MXene materials will provide a general platform for next‐generation self‐powered electronics.

Although Mn2+ additive alleviates the dissolution issue of Mn-based cathodes in aqueous zinc-ion batteries (ZIBs), problems including complex side reactions and abnormal capacity fluctuation pose new challenges for their large-scale...

MXenes are an emerging class of 2D transition metal carbides and nitrides. They have been widely used in flexible electronics owing to their excellent conductivity, mechanical flexibility, and water dispersibility. In this study, the electrode and active layer applications of MXene materials in electronic skins are realized. By utilizing vacuum filtration technology, few‐layer MXene electrodes are integrated onto the top and bottom surfaces of the 3D polyacrylonitrile (PAN) network to form a stable electronic skin. The fabricated flexible device with Ti3C2Tx MXene electrodes outperforms those with other electrodes and exhibits excellent device performance, with a high sensitivity of 104.0 kPa−1, fast response/recovery time of 30/20 ms, and a low detection limit of 1.5 Pa. Furthermore, the electrode and the constructed MXene/PAN‐based flexible pressure sensor exhibit robust mechanical stability and can survive 240 bending cycles. Such a robust, flexible device can be enlarged or folded like a jigsaw puzzle or origami and transformed from 2D to 3D structures; moreover, it can detect tiny movements of human muscles, such as movements corresponding to sound production and intense movements during bending of fingers.

As a typical family of two-dimensional (2D) materials, MXenes present physiochemical properties and potential for use in energy storage applications. However, MXenes suffer some of the inherent disadvantages of 2D materials, such as severe restacking during processing and service and low capacity of energy storage. Herein, a MXene@N-doped carbonaceous nanofiber structure is designed as the anode for high-performance sodium-and potassium-ion batteries through an in situ bioadsorption strategy; that is, Ti 3 C 2 T x nanosheets are assembled onto Aspergillus niger biofungal nanoribbons and converted into a 2D/1D heterostructure. This microorganism-derived 2D MXene-1D N-doped carbonaceous nanofiber structure with fully opened pores and transport channels delivers high reversible capacity and long-term stability to store both Na + (349.2 mAh g −1 at 0.1A g −1 for 1000 cycles) and K + (201.5 mAh g −1 at 1.0 A g −1 for 1000 cycles). Ion-diffusion kinetics analysis and density functional theory calculations reveal that this porous hybrid structure promotes the conduction and transport of Na and K ions and fully utilizes the inherent advantages of the 2D material. Therefore, this work expands the potential of MXene materials and provides a good strategy to address the challenges of 2D energy storage materials. KEYWORDS: biosorption, Ti 3 C 2 T x MXenes, porous hybrid fibers, sodium-ion batteries, potassium-ion batteries, density functional theory calculations