Lanthanum nitrate as aqueous electrolyte additive for favourable zinc metal electrodeposition

Abstract

Aqueous zinc batteries are appealing devices for cost-effective and environmentally sustainable energy storage. However, the zinc metal deposition at the anode strongly influences the battery cycle life and performance. To circumvent this issue, here we propose the use of lanthanum nitrate (La(NO3)3) as supporting salt for aqueous zinc sulfate (ZnSO4) electrolyte solutions. Via physicochemical and electrochemical characterizations, we demonstrate that this peculiar electrolyte formulation weakens the electric double layer repulsive force, thus, favouring dense metallic zinc deposits and regulating the charge distribution at the zinc metal|electrolyte interface. When tested in Zn||VS2 full coin cell configuration (with cathode mass loading of 16 mg cm−2), the electrolyte solution containing the lanthanum ions enables almost 1000 cycles at 1 A g−1 (after 5 activation cycles at 0.05 A g−1) with a stable discharge capacity of about 90 mAh g−1 and an average cell discharge voltage of ∼0.54 V.

Engineering a self-adaptive electric double layer on both electrodes for high-performance zinc metal batteries

“…Furthermore, previous studies proved that the ZnS component probably originates from the reduction of SO 4 . 2–53…”

“…1a), a layer of positively charged counter ions (Zn 2+ ) and a large number of water molecules are tightly adsorbed on the negatively charged Zn anode surface to form a traditional EDL, which is attributed to the electrostatic repulsion and electrostatic shielding effect leading to the dispersion of the counter ions in the diffusion layer to form a thicker EDL. 28 Under the EDL repulsive force, the 2D diffusion of Zn 2+ to the easy-to-deposit sites nucleates where the inhomogeneous electric field causes the 2D diffusion of Zn 2+ to these nucleation sites for further growth, resulting in the formation of a dispersed and loose Zn deposition layer. 29 In addition, the free and the solvent molecules (water molecules) of the solvation layer in the EDL also participate in the HER reaction and form by-products.…”

Tannic acid assisted metal–chelate interphase toward highly stable Zn metal anodes in rechargeable aqueous zinc-ion batteries

“…In comparison, the TA@Zn electrode exhibits a stable 3D diffusion after shorter 2D diffusion (within 50 s), reflecting the shielded 2D diffusion process on the metal–chelate interphase. During the 3D diffusion, the absorbed Zn 2+ ions are locally reduced at the initial absorption sites, which is facile for the formation of dispersive nucleation sites, thus benefiting the uniform Zn deposition ( Zhao et al, 2022 ).…”

Artificial Interphase Layer for Stabilized Zn Anodes: Progress and Prospects

“…Strategic efforts have been devoted into this realm, mainly encompassing structure design, [ 26 ] artificial interphase layer (AIL) construction, [ 27–29 ] and electrolyte optimization. [ 30 ] Among them, AILs normally harvest the most comprehensive functions pertaining to homogenizing nucleation sites, guiding (002) plane growth, aiding ion desolvation, and accelerating mass transfer. Moreover, benefiting from the simple preparation process and scalable production potential, direct construction of an AIL over commercial Zn foil has become one of the most straightforward and appealing strategies to improve the performance of Zn anode.…”

“…Strategic efforts have been devoted into this realm, mainly encompassing structure design, [26] artificial interphase layer (AIL) construction, [27][28][29] and electrolyte optimization. [30] Among them, AILs normally harvest the most The burgeoning Li-ion battery is regarded as a powerful energy storage system by virtue of its high energy density. However, inescapable issues concerning safety and cost aspects retard its prospect in certain application scenarios.…”