Lithium-ion batteries (LIBs) dominate the field of energy storage due to their high specific energy density and long cycle life. However, the scarcity of lithium resources, potential safety issues, and high cost severely restrict their further large-scale energy storage applications. It is thus urgent to investigate other battery systems beyond LIBs. Alkali metal ions (Na+ and K+) with higher abundance and multivalent charge carriers (i.e., Zn2+, Mg2+, Al3+, etc.) have attracted much attention. Although sodium-ion batteries (SIBs) and potassium-ion batteries (KIBs) have the similar chemical properties to Li, they have lower energy density (i.e., 100-120 W·h/kg, 150-170 W/kg), toxic and flammable electrolytes, high operating costs, and safety hazards. Magnesium-ion batteries (MIBs) and aluminum-ion batteries (AIBs) involve multi-electron redox reactions. Although they can theoretically achieve greater specific capacity and energy density, the positive electrode materials available are just a few compounds, affecting their overall development. In addition, the passivation of the Mg anode greatly prevents a further transport of Mg2+. AIBs are in the primary development stage because of the formation of Al2O3 layers on the anode, leading to the corrosion of aluminum electrodes, decreased battery efficiency and low cycling stability.Among all available energy storage systems, aqueous zinc-ion batteries (AZIBs) are considered as a most promising large-scale energy storage due to their lower cost, higher cycling stability, aqueous electrolyte, and safe battery manufacturing process. AZIBs can directly use metallic zinc as a negative electrode material, and they also have unique advantages, such as high theoretical capacity (i.e., 820 mA·h/g and 5 855 mA·h/cm2), low redox potential (i.e., -0.76 V vs. SHE), abundant crustal reserves (i.e., 300 times greater than that of lithium), and good stability in the presence of oxygen and humid atmosphere. Multivalent AZIBs allow multiple electron transfers during the electrochemical reaction, providing an opportunity for achieving high energy and power density. In addition, compared to flammable organic electrolytes, the aqueous electrolytes typically used in AZIBs have lower cost, safer characteristics, and higher ionic conductivity.AZIBs have been developed since the invention of the Voltaic Pile (Zn-Ag) by Alessandro Volta. In 1870-1969, a large-scale production led to the invention of zinc-carbon batteries (i.e., Zn|NH4Cl|MnO2) and alkaline zinc-manganese batteries (i.e., Zn|KOH|MnO2), which are still used. In 1986, Yamamoto used weak acidic electrolytes instead of alkaline electrolytes to improve the reversibility of zinc-manganese batteries. In late 2011, Kang proposed a concept of “zinc-ion batteries” and confirmed the reversible insertion/extraction reaction of zinc ions in manganese dioxide in a zinc sulfate electrolyte system. Since then, various rechargeable battery systems based on near-neutral aqueous electrolytes (i.e., zinc-manganese, zinc-vanadium, zinc-cobalt, and zinc-iodine) have been developed. The existing work on AZIBs deals with aqueous solutions containing ZnSO4, ZnCl2, or Zn(CF3SO3)2 as an electrolyte with a high safety and a reversibility.There are numerous reports on the extensive research on AZIBs, i.e., zinc metal anode, cathode materials, electrolyte engineering, and potential applications. However, there exist still some challenges in the development of these batteries. For instance, the cathode materials suffer from the issues like structural instability, poor conductivity, and dissolution. The zinc anode has inevitable dendrite formation, hydrogen evolution reactions, surface corrosion, and passivation. The aqueous electrolyte has a low voltage window and corresponding parasitic reactions. In addition, most studies are also conducted under mild laboratory conditions without considering the entire battery system, including inactive components.Summary and prospects Rechargeable aqueous zinc-ion batteries based on neutral or weakly acidic electrolyte systems have been developed. However, there are still some challenges in the current battery systems such as low energy density and short cycle life. This review focused on the fundamental scientific issues associated with some aspects of AZIBs, and provided a comprehensive summary of the latest advancements in cathode materials, anode materials, electrolyte materials, and inactive component materials (such as separators, current collectors, and binders). The core issues and research strategies associated with each component were discussed., Some perspectives on the fundamental issues for high-performance water-based zinc-ion batteries were proposed based on the battery structure and electrochemical operating mechanisms.The existing work on AZIBs are mostly carried out in the laboratory, mainly single aspects of evaluation and lacking comprehensive assessments. From small button cells to large-scale pouch cells and prismatic cells, some issues and defects could be magnified, and the impact of side reactions on the electrochemical performance became more apparent. The future research and application of aqueous zinc-ion batteries could require a further exploration of their fundamental issues and multivariate optimization of battery performance.