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.

In the present work, the electrochemical degradation and structural evolution of xLi 2 MnO 3 • (1-x)LiMn 1/3 Ni 1/3 Co 1/3 O 2 (x = 0.3, 0.5, and 0.7) materials and the role of Li 2 MnO 3 component during electrochemical cycling are systematically studied through careful analysis of electrochemical data, ex-situ XRD, and HR-TEM observations. The materials consisting of higher Li 2 MnO 3 content show better cyclic performance with more significant voltage decay compared to that of xLi 2 MnO 3 • (1-x)LiMn 1/3 Ni 1/3 Co 1/3 O 2 electrodes with low Li 2 MnO 3 content. The electrochemical degradation of xLi 2 MnO 3 • (1-x)LiMn 1/3 Ni 1/3 Co 1/3 O 2 electrodes upon cycling not only results from the remarkably increase in impedance caused by the damage of the electrode surface, in particular for low Li 2 MnO 3 content; but also arises from structural rearrangement, especially for high Li 2 MnO 3 content. Upon cycling, high Li 2 MnO 3 content in the crystal structure of lithium-rich transition metal oxides can stabilize the electrode\electrolyte interface at high potentials, facilitates the rapid formation of cracks and porosity in the cycled electrodes, and promotes the distortions and breakdown of the original well-layered lattice.

No abstract