Rechargeable batteries have been used to power various electric devices and store energy from renewables, but their toxic components (namely, electrode materials, electrolyte, and separator) generally cause serious environment issues when disused. Such toxicity characteristic makes them difficult to power future wearable electronic devices. Now an environmentally friendly and highly safe rechargeable battery, based on a pyrene-4,5,9,10-tetraone (PTO) cathode and zinc anode in mild aqueous electrolyte is presented. The PTO-cathode shows a high specific capacity (336 mAh g ) for Zn storage with fast kinetics and high reversibility. Thus, the PTO//Zn full cell exhibits a high energy density (186.7 Wh kg ), supercapacitor-like power behavior and long-term lifespan (over 1000 cycles). Moreover, a belt-shaped PTO//Zn battery with robust mechanical durability and remarkable flexibility is first fabricated to clarify its potential application in wearable electronic devices.

A low-cost CoMoP@C electrocatalyst exhibits high efficiency and stable HER performance superior to commercial 20% Pt/C, and can directly work in seawater for the HER with a Faradaic efficiency of 92.5%.

Given the low cost, ease of fabrication, high safety, and environmental‐friendly characteristics, aqueous rechargeable batteries using mild aqueous solutions as electrolytes (pH is close to 7) and a monovalent/multivalent metal ion as charge carrier, are attracting extensive attention for energy storage. However, accompanied by advantages of mild aqueous electrolyte mentioned above, there are some challenges that stand in the way of the development of these aqueous rechargeable batteries, such as the narrow stable electrochemical window of water, instability of electrode materials, undesired side reactions, etc. In recent years, a massive effort is devoted to overcoming the drawbacks, and some encouraging works have arisen. In this review, the latest advances of electrolyte and electrode materials in aqueous batteries based on monovalent ion (Li+, Na+, K+) and multivalent ion (Zn2+, Mg2+, Ca2+, Al3+) are briefly reviewed.