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The poor performance of Zn electrode in aqueous electrolytes prevents the practical application of aqueous zinc‐ion batteries (AZIBs). Here, 2‐Pyrrolidinone (Pr) is introduced into conventional ZnSO4 electrolytes as additive and only 3 vol.% addition (Pr−to−H2O volume ratio) enables boosted performance. The Pr molecules are preferentially adsorbed on the surface of Zn electrodes to promote the uniform deposition of Zn ions and modulate the solvation structure of Zn2+ to inhibit the side reactions. As a result, the Zn electrode is boosted to run over 1200 h during charge/discharge cycling processes and delivers high average coulombic efficiency (CE) of 99.9 % under 1 mA cm−2, 1 mAh cm−2. Even under harsh testing conditions of 20 mA cm−2 and 20 mAh cm−2, Zn electrode still run over 100 h, which is much longer than that at pristine electrolyte (25 h). Moreover, the Zn||MnO2 full cells with the Pr additive exhibit a high capacity of 201 mAh g−1 and good capacity retention of 89 % after 550 cycles at 0.5 A g−1. [ABSTRACT FROM AUTHOR]

The practical application of aqueous zinc‐ion batteries (AZIBs) is significantly limited by poor reversibility and stability of the Zn anode. Here, the first time addition of trace organic gamma butyrolactone (GBL) is reported to a typical ZnSO4 electrolyte to controllably manipulate the electrolyte structure and interface. Judiciously combined experimental characterization and theoretical computation confirm that the GBL additive weakens the bonding strength between Zn2+ ion and solvated H2O and rearranges the "Zn2+−H2O−SO42– GBL" bonding network to reduce water activity and suppress corrosion and side products. The GBL molecules preferentially absorb on the surface of the Zn anode to give a uniform and compact Zn deposition. As a result, the Zn anode is boosted to run over 3105 cycles (6210 h) with average Coulombic efficiency of 99.93% under 1 mA cm–2 and 1 mAh cm–2, and exhibit stable cycling for 1170 h under harsh testing conditions of 10 mA cm–2 and 10 mAh cm–2. Additionally, the Zn–MnO2 full cells using the ZnSO4–GBL electrolyte exhibit a high capacity of 287 mAh g–1 at 0.5 A g–1 and good capacity retention of 87% following 400 cycles. These findings will be of immediate benefit to design low cost AZIBs for clean energy storage. [ABSTRACT FROM AUTHOR]

Complexes of C11H10N2Cu2Br3 (1) and C22H20N4Cu8I10 (2) [C22H20N4 = 1,1"‐(1,2‐ethanediyl)‐bis‐4,4′‐bipyridinium] were synthesized via the microwave‐assisted solvo‐thermal reactions of C22H20N4Br2, CuSO4·5H2O, and NaX (X = Br, I) and characterized by XRD, FTIR, and thermogravimetric analysis. The crystal structures were determined by single‐crystal X‐ray diffraction analyses. C11H10N2Cu2Br3 crystallized in the monoclinic space group C2/c (no. 15) with lattice parameters a = 24.658(3) Å, b = 6.71(9) Å, c = 17.368(9) Å, β = 98.274(1)°, V = 2847.7(1) Å3, whereas C22H20N4Cu8I10 crystallized in the monoclinic space group P21/n (no. 14) with lattice parameters a = 7.392(2) Å, b = 20.809(7) Å, c = 25.412(7) Å, β = 92.06(8) °, V = 3906.6(8) Å3. Complex 1 showed a 2D layered structure composed of [Cu4Br6]– chains connected via 1,1"‐(1,2‐ethanediyl)‐bis‐4,4′‐bipyridinium ligands. Complex 2 possessed a 3D framework, in which puckered [Cu8I10]2– layers were linked by organic ligands. The thermogravimetric analysis indicated that both two complexes were stable up to 230 °C and 170 °C, respectively. [ABSTRACT FROM AUTHOR]