The commercialization of aqueous Zn-ion batteries (AZIBs) for power-grid energy storage systems is hindered by the safety concerns arising from the Zn dendrite growth. The primary approach in addressing this issue is to induce planar depositions. However, modulating the Zn dissolution process which directly reshapes surface morphology and reserves growth sites has long been overlooked. Herein, by utilizing ester compounds as an illustration, it is revealed that engineering the dissolution energy barrier is a pivotal factor in promoting homogeneous Zn dissolution. Ester adsorbents effectively redistribute charge densities at the electrode-electrolyte interface due to the presence of zincophilic ester functional group and conductive pi-conjugation structure. This effect eventually facilitates Zn dissolution across the surface, transforming the potholed and defective dissolution morphology into a smooth and consistent form. Thus, enhanced cycling stability can be achieved in both half-cells and full-cells, offering an extensive lifespan of thousands of hours for the dissolution and deposition cycles. This work provides a principle for the selection of Zn dissolution improvers to suppress Zn metal dendrite growth by regulating Zn dissolution behavior. The previously disregarded problem of pit formation, which arises from uncontrolled Zn dissolution, has been successfully resolved by manipulating the dissolution energies. Conjugated adsorbents effectively modulate the charge distribution at the electrode-electrolyte interface, engineering dissolution energies and facilitating uniform morphological evolution. image

Because of the high safety and environmental friendliness, aqueous zinc-ion batteries have gained a lot of attention in recent years. Prussian blue and its analogues are regarded as a promising cathode material of zinc-ion batteries. Manganese hexacyanoferrate is appropriate among them due to its high operating voltage, large capacity, and cheap price. However, the poor cycling stability of manganese hexacyanoferrate, mainly caused by transition metal dissolution, side reaction, and phase transition, greatly restricts its practical application. In this work, gelatin is used to limit the content of free water in the electrolyte, thus reducing the dissolution effect of transition metal manganese. The introduction of gelatin improves the durability of the Zn anode as well. The optimized MnHCF/gel-0.3/Zn battery displays a high reversible capacity (120 mAh·g-1 at 0.1 A·g-1), an excellent rate performance (42.7 mAh·g-1 at 2 A·g-1), and a good capacity retention (65% at 0.5 A·g-1 after 1000 cycles).

Aqueous rechargeable zinc–iodine batteries have received increasing attention in the field of portable electronics due to their high safety, low‐cost, and great electrochemical performance. However, the insulated nature of iodine and the unrestricted shuttle effect of soluble triiodide seriously limit the lifespan and Coulombic efficiency (CE) of the batteries. Herein, a high‐performance zinc–iodine energy storage system based on the hydrothermal reduced graphene oxide (rGO) and a high concentration zinc chloride water‐in‐salt electrolyte are promoted. The 3D microporous structures and outstanding electrical conductivity of rGO make it an excellent host for iodine, while the water‐in‐salt electrolyte effectively suppresses the shuttle effect of triiodide and improves the CE of the system. As a result, an ultra‐high I 2 mass loading of 25.33 mg cm −2 (loading ratio of 71.69 wt.%) is realized during the continuous charging/discharging process. The batteries deliver a high capacity of 6.5 mAh cm −2 at 2 mA cm −2 with a much‐improved CE of 95% and a prominent rate performance with capacity of 1 mAh cm −2 at 80 mA cm −2 . A stable long‐term cycling performance is also achieved with capacity retention of 2 mAh cm −2 after 2000 cycles at 50 mA cm −2 .

Aqueous zinc ion batteries (AZIBs) are the promising candidate for energy storage where safety and low cost are the major concerns. However, the uneven and random electrodeposition of Zn has become a serious impediment to the deep recharging of AZIBs. Conventional modifications on zinc substrate can promote homogenous zinc deposition initially, but not sustainably. Here, an oxidized polyacrylonitrile (OPAN) membrane with a conjugated planar structure is proposed as a zinc ion battery separator. This separator can continuously regulate the growth of Zn with (002) texture to inhibit dendrites. In addition, the separator has a fast Zn2+ ion transfer, which can spontaneously repel SO42- and relieve side reactions. As a result, the Zn-symmetric batteries show cycle lifetime of more than 1300 hours at 1 mA cm-2 and 1 mA h cm-2, and kept stable for more than 160 hours even at 65% high discharge of depth (DOD). The MnO2//Zn full celled assembled with an OPAN separator had very little decay for 5000 cycles at 2 A g-1. This work provides a new method for realizing the continuous and uniform deposition of Zn metals, which also provides a new route for batteries with metallic anodes.

Among the various energy storage systems, symmetric aqueous batteries (SABs) have attracted increasing attention due to their low cost, high convenience, and intrinsic safety. However, the available bipolar materials for SABs are limited and their practical scenarios remain scarce. Herein, Prussian blue analogues (PBAs) materials with bipolarity are used to construct SABs, by utilizing the two separated redox platforms at cathodes and anodes, respectively. Meanwhile, the phase transition that occurred in the two-charge-transfer process is highly inhibited by dividing the two redox centers into separated charging/discharging processes, leading to a much-improved structural stability of the PBAs electrodes. Consequently, the constructed symmetric cells exhibit an enhanced cyclability with 1500 cycles and the polarity invertible capability which enables longer life and safer operation. Furthermore, various application scenarios have been promoted based on different electrolytes, including fibrous SABs, low-temperature SABs, and seawater SABs. This study reveals a universal strategy of SABs construction using PBAs materials for practical application.

Commercialization of aqueous batteries is mainly hampered by their low energy density, owing to the low mass loading of active cathode materials. In this work, a MnO2 cathode structure (MnO2 /CTF) is designed to modify the MnO2 /collector interface for enhanced ion transportation properties. Such a cathode can achieve ultrahigh mass loading of MnO2 , large areal capacity, and high energy density, with excellent cycling stability and rate performance. Specifically, a 0.15 mm thick MnO2 /CTF cathode can realize a mass loading of 20 mg cm-2 with almost 100% electrochemical conversion of MnO2 , providing the maximum areal capacity of 12.08 mA h cm-2 and energy density of 191 W h kg-1 for Zn-MnO2 /CTF batteries when considering both cathode and anode. Besides the conventional low energy demonstrations, such a Zn-MnO2 /CTF battery is capable of realistic applications, such as mobile phones in our daily life, which is a promising alternative for wearable electronics.

The liquid electrolyte in conventional zinc/manganese dioxide (Zn/MnO2) batteries conduces to the capacity limitation of one‐electron redox from MnO2 to MnOOH, as well as undesired Mn loss with capacity deterioration. Herein, to conquer these challenges, a new idea is proposed on the precise proton redistribution in the hydrogel electrolyte for the preferred two‐electron redox reaction. Specifically, an acidic layer in the hydrogel adjoins the MnO2 cathode to maintain the two‐electron redox, a neutral layer adjoins the zinc anode to inhibit the dendrite growth, which is separated by a mildly alkaline layer to immobilize the proton distribution. The two‐electron redox of MnO2/Mn2+ and anode protection are demonstrated to play key roles in battery performance. Such a battery presents specific capacities of 516 mA h g−1 at 0.05 A g−1, as well as a capacity retention of 93.18% at 5 A g−1 after 5000 cycles without extra Mn2+ addition in the electrolyte. More importantly, fibrous Zn/MnO2 batteries using the tri‐layer electrolyte can sustain 2000 cycles with high initial capacity of 235 mAh g−1 at 1 A g−1. After 6000 times folding in 180°, it can maintain 99.54% capacity. When integrated into user's clothing or portable accessories, the fibrous battery is demonstrated as a great potential in wearable electronics.

As one of the most promising candidates in wearable energy storage devices, aqueous fibrous zinc metal batteries (AFZMBs) remain limited by some severe challenges, such as short life span and unstable capacity performance, etc. In this work, the stability of AFZMB is extended by fabricating an innovative stratified deposition framework (SDF) anode. The as-prepared SDF electrode can achieve a stratified deposition of Zn metals from the bottom layer to the top layer due to the different overpotentials and binding energy of Zn deposition. Compared with commercial Zn fibers, this dexterous structure provides enough deposition space for Zn metals between the separator and the electrode, dramatically alleviating conventional dendrite puncture and prolonging life expectancy by an order of magnitude. It is found that SDF/AFZMB exhibits a long circulation of 2000 cycles with 89.0% capacity retention at 5 C with superior flexibility, demonstrating potential for application in future wearable electronics.

In article number 2100214, Yagang Yao, Guo Hong and co-workers improve the cycling stability of the aqueous fibrous zinc metal batteries by controlling the zinc deposition priority from bottom to surface in an innovative stratified deposition framework anode, which minimizes the growth of zinc dendrites and boosts the development of wearable devices.