are highly promising thanks to several advantages: (1) zinc metal possesses high specific capacities (820 mAh g −1 and 5855 mAh cm −3 ); [6] (2) zinc metal has high compatibility in water and a reasonably low electrochemical potential (−0.76 V vs SHE), which enables its application of aqueous battery system with extremely high safety; [7] (3) zinc has higher abundance than lithium in the earth crust, and the mature production technology makes the price of zinc extremely costeffective. [8] However, zinc metal's performance in aqueous ZIBs suffers from several problems, particularly dendrite formation. [9] Many factors can contribute to zinc-dendrite formation, especially the uneven distribution of surface charge density at the anode and the inhomogeneous ion flux in the electrolyte, causing zinc to deposit unevenly and form zinc tips on the surface of the anode. Such as-formed zinc-metal tips tend to exhibit locally concentrated surface charge density and promote the growth of zinc over other areas, which is often referred to as the notorious "tip effect". [10] These zinc tips eventually grow into prominent zinc dendrites during cycling and finally cause an internal battery short circuit (Figure 1, top panel). Thus, a stable zinc-metal anode with dendrite-free deposition behavior is a key requirement for the broad application of aqueous ZIBs.In recent years, suppressing the zinc-dendrite growth in aqueous zinc-ion batteries has attracted widespread research interest. Various approaches have been adopted to fulfill this goal, including optimizing electrolyte components, [11] applying 3D current collectors, [12] and constructing artificial interphases. [13] Constructing artificial interphases before battery assembly is an easy and highly efficient strategy to enable a highly stable zinc anode in operating batteries. [14] These artificial protective layers are generally proposed to introduce physiochemical interactions with zinc, and thus realize its stable deposition. However, most reported artificial protective layers were prepared with a relatively high thickness, [14,15] which would inevitably harm the gravimetric and volumetric specific capacities of the ZIBs. Therefore, designing thin artificial protective layers, which can still achieve a dendrite-free zinc-deposition behavior while minimizing the impact on battery energy density, becomes critical for zinc-metal anodes. Considering the high Young's modulus of zinc, [16] constructing a protective layer to suppress zinc-dendrite growth is a very challenging task.Aqueous zinc-ion batteries are regarded as ideal candidates for stationary energy-storage systems due to their low cost and high safety. However, zinc can readily grow into dendrites, leading to limited cycling performance and quick failure of the batteries. Herein, a novel strategy is proposed to mitigate this dendrite problem, in which a selectively polarized ferroelectric polymer material (poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE))) is employed as a surface protective layer on zinc ...

Energy harvesting modules play an increasingly important role in the development of autonomous self‐powered microelectronic devices. MXenes (i.e., 2D transition metal carbide/nitride) have recently emerged as promising candidates for energy applications due to their excellent electronic conductivity, large specific surface area, and tunable properties. Herein, a perspective on using MXenes to harvest energy from various sources in the environment is presented. First, the characteristics of MXenes that facilitate energy capturing are systematically introduced and the preparation strategies of MXenes and their derived nanostructures tailored toward such applications are summarized. Subsequently, the harvesting mechanism of different energy sources (e.g., solar energy, thermoelectric energy, triboelectric energy, piezoelectric energy, salinity‐gradient energy, electrokinetic energy, ultrasound energy, and humidity energy) are discussed. Then, the recent progress of MXene‐based nanostructures in energy harvesting, as well as their applications, is introduced. Finally, opinions on the existing challenges and future directions of MXene‐based nanostructure for energy harvesting are presented.

Crystallography modulation of aqueous zinc metal anodes can effectively inhibit their dendrite growth and unfavorable side reactions. However, the ability to directly endow the commercial Zn foils with specific texture is still lacking. In this study, a grain-size-assisted cold-rolling approach is developed to reshape and unify the commercial Zn foils into strong (002) textured Zn. It is revealed that the grain size strongly affects the (002) texture formation during the plastic deformation. By proper annealing treatment, the grain sizes of commercial Zn foils are controlled at ∼30 μm, which favors the formation of strong (002) texture during the following cold-rolling process. The resultant (002) textured Zn foils show better resistance to side reactions and dendrite growth when used as aqueous metal anodes. The strong (002) texture endows the Zn anode with long cycling stability in Zn//Zn symmetric batteries (2800 h at 0.1 mA cm–2, 100 h at 10 mA cm–2) and Zn//porous carbon capacitors (6000 cycles at 2 A g–1). The strategy demonstrated in this work unifies the different textures of commercial Zn foils into strong (002) texture and provides a scalable pathway toward highly reversible Zn anodes for aqueous zinc-ion energy storage devices.

The addition of certain additives during intercalation and surface modification can result in MXene-based materials with exceptional performances.

Sulfur‐based batteries are regarded as potent candidates for next‐generation high‐energy and low‐cost energy storage systems. However, sulfur‐based batteries still face substantial obstacles on the cathode side (e.g., low conductivity and sluggish reaction kinetics of sulfur) and the anode side (e.g., dendrite growth), severely hindering their utilization. MXenes (i.e., 2D transition metal carbides, nitrides, and carbonitrides), as an emerging member of the 2D material family, possess unique electrochemical and electronic properties, which make them attractive materials to enhance the performance of sulfur‐based batteries. In this article, a comprehensive review of the research progress on using MXenes in sulfur‐based batteries is provided. The basics of MXene and sulfur‐based batteries are introduced first, wherein the merits of applying MXenes in sulfur‐based batteries are discussed. Subsequently, the progress in this field is systematically summarized in terms of the roles of MXene in sulfur‐based batteries, including MXene as sulfur host, MXene‐based composite as sulfur host, MXene‐based separator modification, and MXene‐based advanced electrodes. In the end, recommendations for specific future research directions to advance the development of MXenes for sulfur‐based batteries are outlined.