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...

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.

Topotactically synthesized hierarchical zigzag Na1.25V3O8 nanowires with an optimized morphology and a crystal structure exhibit excellent performances as Na-ion battery cathodes.

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The in situ structural evolution of the catalyst was successfully achieved by in situ electrochemical dealloying approach. Direct evidence of O–O bond formation was probed by operando ATR FT-IR, suggesting the direct O2 evolution mechanism.

Lithium–sulfur batteries have attracted extensive attention because of their high energy density. However, their application is still impeded by the inherent sluggish kinetics and solubility of intermediate products (i.e., polysulfides) of the sulfur cathode. Herein, graphene‐supported Ni nanoparticles with a carbon coating are fabricated by directly carbonizing a metal–organic framework/graphene oxide composite, which is then dispersed on a commercial glass fiber membrane to form a separator with electrocatalytic activity. In situ analysis and electrochemical investigation demonstrate that this modified separator can effectively suppress the shuttle effect and regulate the catalytic conversion of intercepted polysulfides, which is also confirmed by density functional theory calculations. It is found that Ni–C sites can chemically interact with polysulfides and stabilize the radical S3•− through NiS bonds to enable fast dynamic equilibrium with S62−, while Ni nanoparticles reduce the oxidation barrier of Li2S and accelerate ion/electron transport. As a result, the corresponding lithium–sulfur battery shows a high cycle stability (88% capacity retention over 100 cycles) even with a high sulfur mass loading of 8 mg cm−2 and lean electrolyte (6.25 µL mg−1). Surprisingly, benefitting from the improved kinetics, the battery can work well at −50 °C, which is rarely achieved by conventional Li–S batteries.

Conventional intercalation compounds for lithium‐ion batteries (LIBs) suffer from rapid capacity fading and are even unable to charge–discharge with temperature decline, owing to the sluggish kinetics and solvation/desolvation process. In this work, a high‐performance rechargeable battery at ultralow temperature is developed by employing a nanosized Ni‐based Prussian blue (NiHCF) cathode. The battery delivers a high capacity retention of 89% (low temperature of −50 °C) and 82% (ultralow temperature of −70 °C) compared with that at +25 °C. Various characterizations and electrochemical investigations, including operando Fourier transform infrared spectra, in situ X‐ray diffraction, cyclic voltammetry response, and galvanostatic intermittent titration technique are carried out to detect the structural stability and electrochemical behavior at different temperatures. It turns out that the pseudocapacitive behavior drives the desolvation process at the interface, while fast diffusion in the bulk electrode accelerates the movement of Li + from the interface to the bulk materials. The unique synergistic features of intercalation pseudocapacitance at the electrolyte/electrode interface and high diffusion coefficient in the bulk electrode enables the NiHCF cathode with excellent low temperature performance. These findings offer a new direction for the design of LIBs operated at low temperature.

The development of inexpensive electrode materials with a high volumetric capacity and long cycle-life is a central issue for large-scale lithium-ion batteries. Here, we report a nanostructured porous FeN anode fully encapsulated in carbon microboxes (FeN@C) prepared through a facile confined anion conversion from polymer coated FeO microcubes. The resulting carbon microboxes could not only protect the air-sensitive FeN from oxidation but also retain thin and stable SEI layer. The appropriate internal voids in the FeN cubes help to release the volume expansion during lithiation/delithiation processes, and FeN is kept inside the carbon microboxes without breaking the shell, resulting in a very low electrode volume expansion (the electrode thickness variation upon lithiation is ∼9%). Therefore, the FeN@C electrodes maintain high volumetric capacity (1030 mA h cm based on the lithiation-state electrode volume) comparable to silicon anodes, stable cycling performance (a capacity retention of over 91% for 2500 cycles), and excellent rate performance. Kinetic analysis reveals that the FeN@C shows an enhanced contribution of capacitive charge mechanism and displays typical pseudocapacitive behavior. This work provides a new direction on designing and constructing nanostructured electrodes and protective layer for air unstable conversion materials for potential applications as a lithium-ion battery/capacitor electrode.