RESUMEN
Developing a reasonable design of a lithiophilic artificial solid electrolyte interphase (SEI) to induce the uniform deposition of Li+ ions and improve the Coulombic efficiency and energy density of batteries is a key task for the development of high-performance lithium metal anodes. Herein, a high-performance separator for lithium metal anodes was designed by the in situ growth of a metal-organic framework (MOF)-derived transition metal sulfide array as an artificial SEI on polypropylene separators (denoted as Co9S8-PP). The high ionic conductivity and excellent morphology provided a convenient transport path and fast charge transfer kinetics for lithium ions. The experimental data illustrate that, compared with commercial polypropylene separators, the Li//Cu half-cell with a Co9S8-PP separator can be cycled stably for 2000 h at 1 mA cm-2 and 1 mAh cm-2. Meanwhile, a Li//LiFePO4 full cell with a Co9S8-PP separator exhibits ultra-long cycle stability at 0.2 C with an initial capacity of 148 mAh g-1 and maintains 74% capacity after 1000 cycles. This work provides some new strategies for using transition metal sulfides to induce the uniform deposition of lithium ions to create high-performance lithium metal batteries.
RESUMEN
Dendrite formation and water-triggered side reactions on the surface of Zn metal anodes severely restrict the commercial viability of aqueous zinc-ion batteries (AZIBs). In this work, we introduce erythritol (Et) as an electrolyte additive to enhance the reversibility of zinc anodes, given its cost-effectiveness, mature technology, and extensive utilization in various domains such as food, medicine, and other industries. By combining multiscale theoretical simulation and experimental characterization, it was demonstrated that Et molecules can partially replace the coordination H2O molecules to reshape the Zn2+ solvation sheath and destroy the hydrogen bond network of the aqueous electrolyte. More importantly, Et molecules tend to adsorb on the zinc anode surface, simultaneously inhibit water-triggered side reactions by isolating water and promote uniform and dense deposition by accelerating the Zn2+ diffusion and regulating the nucleation size of the Zn grain. Thanks to this synergistic mechanism, the Zn anode can achieve a cycle life of more than 3900 h at 1 mA cm-2 and an average Coulombic efficiency of 99.77%. Coupling with δ-MnO2 cathodes, the full battery delivers a high specific capacity of 228.1 mAh g-1 with a capacity retention of 76% over 1000 cycles at 1 A g-1.
RESUMEN
Aqueous zinc-ion batteries (AZIBs) directly using zinc metal anodes are promising candidates for grid-scale energy storage systems due to their intrinsic high theoretical capacity, high safety, and environmental friendliness. However, the uncontrolled dendrite growth and water-triggered side reactions seriously plague its practical application. Herein, a cost-effective and green additive, maltodextrin (MD) is presented, to simultaneously guide the smooth Zn deposition and inhibit the occurrence of water-related side reactions. Combing experimental characterizations and theoretical calculations shows that the MD molecules could reconstruct the Helmholtz plane, induces a preferential growth of zinc along the (002) plane, and the optimized regulation of the Zn2+ diffusion path and deposition location also results in the formation of fine-grained Zn deposition layers, thereby inhibiting dendrite growth. In addition, MD molecules readily adsorb to the zinc anode surface, which isolates water molecules from direct contact with the zinc metal, reducing hydrogen precipitation reactions and inhibiting the formation of by-products. Consequently, the Zn||Zn symmetric cell with MD achieves ultra-long stable cycles of up to 5430 h at 1 mA cm-2 and 1 mA h cm-2, and the Cu||Zn asymmetric cell can stable cycle 1000 cycles with an average coulomb efficiency of 99.78%.