Metallic zinc is a promising anode candidate of aqueous zinc‐ion batteries owing to its high theoretical capacity and low redox potential. However, Zn anodes usually suffer from dendrite and side reactions, which will degrade their cycle stability and reversibility. Herein, we developed an in situ spontaneously reducing/assembling strategy to assemble a ultrathin and uniform MXene layer on the surface of Zn anodes. The MXene layer endows the Zn anode with a lower Zn nucleation energy barrier and a more uniformly distributed electric field through the favorable charge redistribution effect in comparison with pure Zn. Therefore, MXene‐integrated Zn anode exhibits obviously low voltage hysteresis and excellent cycling stability with dendrite‐free behaviors, ensuring the high capacity retention and low polarization potential in zinc‐ion batteries.

Rechargeable aqueous zinc‐ion batteries (ZIBs) have garnered tremendous attention in the field of next energy storage devices due to their high safety, low cost, abundant resources, and eco‐friendliness. As an important component of the zinc‐ion battery, the electrolyte plays a vital role in the electrochemical properties, since it will provide a pathway for the migrations of the zinc ions between the cathode and anode, and determine the ionic conductivity, electrochemically stable potential window, and reaction mechanism. In this Minireview, a brief introduction of electrochemical principles of the aqueous ZIBs is discussed and the recent advances of various aqueous electrolytes for ZIBs, including liquid, gel, and multifunctional hydrogel electrolytes are also summarized. Furthermore, the remaining challenges and future directions of electrolytes in aqueous ZIBs are also discussed, which could provide clues for the following development.

The self‐healing of zinc‐ion batteries (ZIBs) will not only significantly improve the durability and extend the lifetime of devices, but also decrease electronic waste and economic cost. A poly(vinyl alcohol)/zinc trifluoromethanesulfonate (PVA/Zn(CF3SO3)2) hydrogel electrolyte was fabricated by a facile freeze/thaw strategy. PVA/Zn(CF3SO3)2 hydrogels possess excellent ionic conductivity and stable electrochemical performance. Such hydrogel electrolytes can autonomously self‐heal by hydrogen bonding without any external stimulus. All‐in‐one integrated ZIBs can be assembled by incorporating the cathode, separator, and anode into hydrogel matrix since the fabrication of PVA/Zn(CF3SO3)2 hydrogel is a process of converting the liquid to quasi‐solid state. The ZIBs show an outstanding self‐healing and can recover electrochemical performance completely even after several cutting/healing cycles.

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Self-charging power systems integrating energy harvesting technologies and batteries are attracting extensive attention in energy technologies. However, the conventional integrated systems are highly dependent on the availability of the energy sources and generally possess complicated configuration. Herein, we develop chemically self-charging aqueous zinc-ion batteries with a simplified two-electrode configuration based on CaV 6 O 16 ·3H 2 O electrode. Such system possesses the capability of energy harvesting, conversion and storage simultaneously. It can be chemically self-recharged by the spontaneous redox reaction between the discharged cathode and oxygen from the ambient environment. Chemically selfrecharged zinc-ion batteries display an initial open-circuit voltage of about 1.05 V and a considerable discharge capacity of about 239 mAh g −1 , indicating the excellent selfrechargeability. Impressively, such chemically self-charging zinc-ion batteries can also work well at chemical or/and galvanostatic charging hybrid modes. This work not only provides a route to design chemically self-charging energy storage, but also broadens the horizons of aqueous zinc-ion batteries.

We report that vertically aligned ZnO nanowire arrays (ZnO NWAs) were fabricated on 3D graphene foam (GF) and used to selectively detect uric acid (UA), dopamine (DA), and ascorbic acid (AA) by a differential pulse voltammetry method. The optimized ZnO NWA/GF electrode provided a high surface area and high selectivity with a detection limit of 1 nM for UA and DA. The high selectivity in the oxidation potential was explained by the gap difference between the lowest unoccupied and highest occupied molecular orbitals of a biomolecule for a set of given electrodes. This method was further used to detect UA levels in the serum of patients with Parkinson's disease (PD). The UA level was 25% lower in PD patients than in healthy individuals. This finding strongly implies that UA can be used as a biomarker for PD.

Among various energy storage devices, aqueous zinc-ion batteries (ZIBs) have captured great attention due to their high safety and low cost. One of the most promising cathodes of aqueous ZIBs is layered vanadium-based compounds. However, they often suffer from the capacity decaying during cycling. Herein, we prepared KV3O8·0.75H2O (KVO) and further incorporated it into a single-walled carbon nanotube (SWCNT) network, achieving freestanding KVO/SWCNT composite films. The KVO/SWCNT cathodes exhibit a Zn2+/H+ insertion/extraction mechanism, resulting in fast kinetics of ion transfer. In addition, the KVO/SWCNT composite films possess a segregated network structure, which offers the fast kinetics of electron transfer and guarantees an intimate contact between KVO and SWCNTs during cycling. As a result, the resultant batteries deliver a high capacity of 379 mAh g–1, excellent rate capability, and an ultralong cycle life up to 10,000 cycles with a high capacity retention of 91%. In addition, owing to the high conductivity and flexibility of KVO/SWCNT films, flexible soft-packaged ZIBs based on KVO/SWCNT film cathodes were assembled and displayed stable electrochemical performance at different bending states.

The reversible capacity of AlCl 4 À intercalation/deintercalation in conventional cathodes of aluminum-ion batteries (AIBs) is difficult to improve due to the large size of AlCl 4 À anions. Therefore, it is highly desirable to realize the intercalation/de-intercalation of smaller Al-based ions. Here, we fabricated polyaniline/single-walled carbon nanotubes (PANI/SWCNTs) composite films and protonated the PANI nanorods. The protonation endows PANI with more active sites and enhanced conductivity. Hyper self-protonated PANI (PANI(H +)) exhibits reversible AlCl 2 + intercalation/de-intercalation during the discharge/charge process. As a result, the discharge capacity of the Al/PANI(H +) battery is twice as high as that of the initial composite films. PANI(H +)@SWCNT electrodes also have a stable cycling life with only 0.003 % capacity decay per cycle over 8000 cycles. Owing to the excellent mechanical properties, PANI(H +)@SWCNT composite films can act as the electrodes of flexible AIBs.