Safety concerns about organic media-based batteries are the key public arguments against their widespread usage. Aqueous batteries (ABs), based on water which is environmentally benign, provide a promising alternative for safe, cost-effective, and scalable energy storage, with high power density and tolerance against mishandling. Research interests and achievements in ABs have surged globally in the past 5 years. However, their large-scale application is plagued by the limited output voltage and inadequate energy density. We present the challenges in AB fundamental research, focusing on the design of advanced materials and practical applications of whole devices. Potential interactions of the challenges in different AB systems are established. A critical appraisal of recent advances in ABs is presented for addressing the key issues, with special emphasis on the connection between advanced materials and emerging electrochemistry. Last, we provide a roadmap starting with material design and ending with the commercialization of next-generation reliable ABs.

Zinc‐based electrochemistry is attracting significant attention for practical energy storage owing to its uniqueness in terms of low cost and high safety. However, the grid‐scale application is plagued by limited output voltage and inadequate energy density when compared with more conventional Li‐ion batteries. Herein, we propose a latent high‐voltage MnO2 electrolysis process in a conventional Zn‐ion battery, and report a new electrolytic Zn–MnO2 system, via enabled proton and electron dynamics, that maximizes the electrolysis process. Compared with other Zn‐based electrochemical devices, this new electrolytic Zn–MnO2 battery has a record‐high output voltage of 1.95 V and an imposing gravimetric capacity of about 570 mAh g−1, together with a record energy density of approximately 409 Wh kg−1 when both anode and cathode active materials are taken into consideration. The cost was conservatively estimated at

Dendrite growth and by-products in Zn metal aqueous batteries have impeded their development as promising energy storage devices.W eu tilize al ow-cost additive, glucose,t om odulate the typical ZnSO 4 electrolyte system for improving reversible plating/stripping on Zn anode for highperformance Zn ion batteries (ZIBs). Combing experimental characterizations and theoretical calculations,weshow that the glucose in ZnSO 4 aqueous environment can simultaneously modulate solvation structure of Zn 2+ and Zn anode-electrolyte interface.T he electrolyte engineering can alternate one H 2 O molecule from the primary Zn 2+ -6H 2 Os olvation shell and restraining side reactions due to the decomposition of active water.Concomitantly,glucose molecules are inclined to absorb on the surface of Zn anode,suppressing the random growth of Zn dendrite.A saproof of concept, as ymmetric cell and Zn-MnO 2 full cell with glucose electrolyte achieve boosted stability than that with pure ZnSO 4 electrolyte.

Research interests and achievements in zinc aqueous batteries, such as alkaline Zn//Mn, Zn//Ni/Co, Zn-air batteries and near-neutral Zn ion and hybrid ion batteries, have surged throughout the world due to their peculiarity of low-cost and high-safety. However, practical application of Zn-based secondary batteries is plagued by restrictive energy and power densities in which an inadequate output plateau voltage and sluggish kinetics are mutually accountable. Here, a novel paradigm high-rate and high-voltage Zn-Mn hybrid aqueous battery (HAB) is constructed with an expanded electrochemical stability window over 3.4 V that is affordable. As a proof of concept, we demonstrate catalyzed MnO 2 /Mn 2+ electrolysis kinetics in HAB via facile introduction of Ni 2+ into the electrolyte. Various spectra techniques are employed including, in situ synchrotron X-ray powder diffraction, ex situ X-ray absorption fine structure and electron energy loss spectrum, to reveal the reversible charge storage mechanism and origin of boosted rate-capability. Density functional theory calculations figure out enhanced active electron states and charge delocalization after This article is protected by copyright. All rights reserved.introducing strong electronegativity Ni. Simulations of reaction pathways confirm enhanced catalyzed electrolysis kinetics by the facilitated charge transfer at active O sites around Ni dopants. These findings significantly advance aqueous batteries a step closer toward practical low-cost application.

While research interest in aqueous batteries has surged due to their intrinsic low cost and high safety, the practical application is plagued by the restrictive capacity (less than 600 mAh g −1 ) of electrode materials. Sulfur-based aqueous batteries (SABs) feature high theoretical capacity (1672 mAh g −1 ), compatible potential, and affordable cost, arousing ever-increasing attention and intense efforts. Nonetheless, the underlying electrochemistry of SABs remains unclear, including complicated thermodynamic evolution and insufficient kinetics metrics. Consequently, multifarious irreversible reactions in various application systems imply the systematic complexity of SABs. Herein, rather than simply compiling recent progress, this Perspective aims to construct a theory-to-application methodology. Theoretically, attention has been paid to a critical appraisal of the aqueous-S-related electrochemistry, including fundamental properties evaluation, kinetics metrics with transient and steady-state analyses, and thermodynamic equilibrium and evolution. To put it into practice, current challenges and promising strategies are synergistically proposed. Practically, the above efforts are employed to evaluate and develop the device-scale applications, scilicet flow-SABs, oxide-SABs, and metal-SABs. Last, chemical and engineering insights are rendered collectively for the future development of high-energy SABs.