Highly Reversible Zn Metal Anodes Enabled by Increased Nucleation Overpotential

Abstract

Dendrite formation severely compromises further development of zinc ion batteries. Increasing the nucleation overpotential plays a crucial role in achieving uniform deposition of metal ions. However, this strategy has not yet attracted enough attention from researchers to our knowledge. Here, we propose that thermodynamic nucleation overpotential of Zn deposition can be boosted through complexing agent and select sodium L-tartrate (Na-L) as example. Theoretical and experimental characterization reveals L-tartrate anion can partially replace H2O in the solvation sheath of Zn2+, increasing de-solvation energy. Concurrently, the Na+ could absorb on the surface of Zn anode preferentially to inhibit the deposition of Zn2+ aggregation. In consequence, the overpotential of Zn deposition could increase from 32.2 to 45.1 mV with the help of Na-L. The Zn-Zn cell could achieve a Zn utilization rate of 80% at areal capacity of 20 mAh cm−2. Zn-LiMn2O4 full cell with Na-L additive delivers improved stability than that with blank electrolyte. This study also provides insight into the regulation of nucleation overpotential to achieve homogeneous Zn deposition.

Employing a chelating agent as electrolyte additive with synergistic effects yields highly reversible zinc metal anodes

“…According to the classical nucleation theory, the larger the nucleation overpotential deposited, the finer the grain size of the zinc deposited. 52 The nucleation overpotential of the CG10 electrolyte (26.4 mV) is slightly larger than that of CG0 (23.9 mV) (Fig. 1c), implying Zn deposition with a finer grain size in the CG10 electrolyte, which is consistent with the ACE results.…”

Restraining the shuttle effect of polyiodides and modulating the deposition of zinc ions to enhance the cycle lifespan of aqueous Zn–I2 batteries

“…The NOP of the battery with PVA electrolyte is increased by approximately 20 mV, suggesting that the battery with PVA electrolyte can provide a strong driving force for Zn nucleation, leading to a dense and homogeneous deposition of zinc ions. 52,57–60 This observation can be verified by the in situ optical visualization investigations in Fig. S8 †.…”

Lotus Effect Inspired Hydrophobic Strategy for Stable Zn Metal Anodes

“…A high overpotential indicates a stronger nucleation driving force, which facilitates to form smaller nucleus radiu, resulting in continuous 3D diffusion. [53][54][55] Drastic voltage fluctuations of Zn||Cu cell can be observed after 50 cycles, owing to the unfavorable side reactions and the formation of Zn dendrites (Figure S18a, Supporting Information). However, the overpotential of SA-Cu@Zn||Cu cell persists in decreasing within 200 cycles, and the voltage gap is only 42 mV even at 900 cycles (Figure S18b, Supporting Information), suggesting the enhanced kinetics for SA-Cu@Zn anode.…”