Zinc metal featuring low cost, high capacity, low potential, and environmental benignity is an exciting anode material for aqueous energy storage devices. Unfortunately, the dendrite growth, limited reversibility, and undesired hydrogen evolution hinder its application. Herein, we demonstrate that MOF ZIF-8 annealed at 500 C (ZIF-8-500) can be used as a host material for high-efficiency (approximately 100%) and dendrite-free Zn plating and stripping because of its porous structure, trace amount of zinc in the framework, and high over-potential for hydrogen evolution. The Zn@ZIF-8-500 anode (i.e., ZIF-8-500 pre-plated with 10.0 mAh cm À2 Zn) is coupled with an activated carbon cathode or an I 2 cathode to form a hybrid supercapacitor or a rechargeable battery, respectively. The supercapacitor delivers a high energy density of 140.8 Wh kg À1 (normalized to the mass of active materials in electrodes) while retaining 72% capacity over 20,000 cycles, and the battery shows a long life of 1,600 cycles.

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.

An ethyl acetate-based electrolyte, which exhibits a high boiling point, a low freezing point, and a sufficient ionic conductivity at ultra-low temperature of À70 C, was developed. Taking advantage of such an electrolyte, Li-ion full cells based on organic electrodes can work well and show outstanding performance within a wide operation temperature range from À70 C to +55 C.

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.

storage. [2][3][4][5][6][7] Among them, aqueous zinc batteries have aroused extensive interest and attention, which benefits from many advantages of zinc anode, including high theoretical capacity (820 mAh g −1 ), appropriate redox potential (−0.762 V vs the standard hydrogen electrode (SHE)), and intrinsic safety in aqueous system. [8][9][10][11][12][13][14][15][16][17][18][19][20] Inspired by conventional Li + storage reaction, intercalation reaction of transition metal oxides are employed to storage Zn 2+ in the mild aqueous solution. For example, Zn 0.25 V 2 O 5 ·nH 2 O, [9] Prussian blue analogue, [15] VO 2 , [17] MnO 2 , [18] Zn 3 V 2 O 7 (OH) 2 ·2H 2 O, [19] CuV 2 O 6 [20] have been used as cathodes for zinc batteries. However, the hydrated Zn 2+ and H + usually result in large volumetric change and serious structural collapse of these inorganic compounds with the insertion of a large amount of hydrated Zn 2+ , [21][22][23][24][25] showing significant capacity fading and limited cycle life. In recent years, the organic compounds containing carbonyl groups have been employed to store Li + and Na + through reversible coordination reaction (i.e., the CO/C-O-Li + /Na + conversion), and thus many batteries based on organic electrodes were proposed by using monovalent ion (Li + /Na + ) as charge carrier. [26][27][28][29][30][31] Then, it was demonstrated that such coordination reaction can also be used to store divalent ions (e.g., Mg 2+ and Zn 2+ ), which evoked the enthusiasm for developing divalent ion batteries using organic electrode. [32][33][34][35][36][37] Very recently, Chen's group reported the first Zn-organic (C 4 Q//Zn) battery with high energy and long life. [38] Chen and co-workers work indicates that it should be a good choice for building zinc batteries to use organics as the alternative to inorganic host materials to store Zn 2+ . However, many organics with carbonyl groups (CO) and/or their reduced products (C-O-) suffer from the inherent instability and solubility in electrolyte. [39][40][41][42][43] It is well known that the solubility can lead to the crossover of electrode active materials between cathode and anode. As a result, expensive ion exchange membranes generally are required to prevent the crossover. [38] Furthermore, owing to the inevitable presence of H + in mild aqueous electrolyte (e.g., aqueous ZnSO 4 electrolyte generally shows a pH value of 4-5), H + can also react with carbonyl groups of organic compounds before or in parallel with the storage of Zn 2+ , which might aggravate the poor cycle life arising from the inherent The newly emerged aqueous Zn-organic batteries are attracting extensive attention as a promising candidate for energy storage. However, most of them suffer from the unstable and/or soluble nature of organic molecules, showing limited cycle life (≤3000 cycles) that is far away from the requirement (10 000 cycles) for grid-scale energy storage. Here, a new aqueous zinc battery is proposed by using sulfur heterocyclic quinone dibenzo[b,i]thianthrene-5,7,12,1...

HIGHLIGHTSFlexible aqueous belt-and fibershaped SIBs with high safety are fabricated Normal saline and cell-culture medium are used directly as electrolytes for SIBs Fiber-shaped SIBs exhibit an electrochemical deoxygenation function

Hydronium-ion batteries are regarded as one of the most promising energy technologies as next-generation power sources, benefiting from their cost effectivity and sustainability merits. Herein, we propose a hydronium-ion battery which is based on an organic pyrene-4,5,9,10-tetraone anode and an inorganic MnO2@graphite felt cathode in an acid electrolyte. Its operation involves a quinone/hydroquinone redox reaction on anode and a MnO2/Mn2+ conversion reaction on cathode, in parallel with the transfer of H3O+ between two electrodes. The distinct operation mechanism affords this hydronium-ion battery an energy density up to 132.6 Wh kg−1 and a supercapacitor-comparable power density of 30.8 kW kg−1, along with a long-term cycling life over 5000 cycles. Furthermore, surprisingly, this hydronium-ion battery works well even with a frozen electrolyte under −40 °C, and superior rate performance and cycle stability remain at −70 °C.

Aqueous zinc (Zn) batteries have been considered as promising candidates for grid‐scale energy storage. However, their cycle stability is generally limited by the structure collapse of cathode materials and dendrite formation coupled with undesired hydrogen evolution on the Zn anode. Herein we propose a zinc–organic battery with a phenanthrenequinone macrocyclic trimer (PQ‐MCT) cathode, a zinc‐foil anode, and a non‐aqueous electrolyte of a N,N‐dimethylformamide (DMF) solution containing Zn2+. The non‐aqueous nature of the system and the formation of a Zn2+–DMF complex can efficiently eliminate undesired hydrogen evolution and dendrite growth on the Zn anode, respectively. Furthermore, the organic cathode can store Zn2+ ions through a reversible coordination reaction with fast kinetics. Therefore, this battery can be cycled 20 000 times with negligible capacity fading. Surprisingly, this battery can even be operated in a wide temperature range from −70 to 150 °C.