A robust gradient solid electrolyte interphase enables fast Zn dissolution and deposition dynamics,Energy & Environmental Science

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A robust gradient solid electrolyte interphase enables fast Zn dissolution and deposition dynamics
Energy & Environmental Science ( IF 32.4 ) Pub Date : 2023-12-05 , DOI: 10.1039/d3ee03422d
Caiyun Chang _{1,

2} , Sanlue Hu _{1,

2} , Titi Li ₁ , Fanbin Zeng ₁ , Dun Wang _{1,

3} , Songde Guo _{1,

3} , Minwei Xu _{1,

2} , Guojin Liang _{1,

2} , Yongbing Tang _{1,

2} , Hongfei Li ₃ , Cuiping Han _{1,

2} , Hui-Ming Cheng _{1,

2,

4}

Affiliation

The construction of a robust solid–electrolyte interphase (SEI) on zinc anode is an effective approach for tackling the high thermodynamic instability and side reactions of Zn-metal anode (ZMA), particularly at high current densities and high utilization ratios. Herein, a ternary aqueous electrolyte with N,N-dimethyltrifluoroacetamide (DMTFA), dimethylformamide (DMF), and H₂O is developed to build a stable SEI. DMTFA is introduced as a functional solvent, which is preferentially decomposed to form a gradient rigid–soft coupling SEI layer. Meanwhile, DMF is added as a co-solvent to suppress the water activity by forming an intermolecular hydrogen bond, thus protecting the as-formed SEI against corrosion. It is found that a 31 nm-thick SEI film with a –CF₃-rich-organic outer layer and a gradient zinc salts-rich-inorganic (e.g., ZnF₂, Zn₃N₂, ZnSO₃, ZnS, ZnO) inner layer delivers excellent structural integrity to block the direct contact of water and ZMA. Moreover, the as-formed SEI exhibits a high compression modulus (23.5 GPa), which is strong enough for extreme stress, such as dendrite puncture. Scanning electrochemical microscopy reveals the electron-insulating feature of the SEI, which can promote the uniform spherical zinc deposition underneath it. Consequently, AZIBs with the gradient SEI achieve ultra-long cycling stability of 4100 h in harsh conditions of 20 mA cm⁻² and 20 mA h cm⁻², super-high cumulative capacity of 41 A h cm⁻², excellent reversibility with average coulombic efficiency of 99.8%, and an 11 000-cycle lifespan for Zn‖NaV₃O₈ cell.

中文翻译：

强大的梯度固体电解质界面可实现锌的快速溶解和沉积动力学

在锌阳极上构建坚固的固体电解质界面（SEI）是解决锌金属阳极（ZMA）的高热力学不稳定性和副反应的有效方法，特别是在高电流密度和高利用率下。在此，开发了一种含有 N,N-二甲基三氟乙酰胺 (DMTFA)、二甲基甲酰胺 (DMF) 和 H ₂ O 的三元水电解质，以构建稳定的 SEI。 DMTFA作为功能溶剂被引入，优先分解形成梯度刚软耦合SEI层。同时，添加DMF作为共溶剂，通过形成分子间氢键来抑制水活度，从而保护所形成的SEI免受腐蚀。研究发现，31 nm 厚的 SEI 膜具有富含 –CF ₃ 的有机外层和富含梯度锌盐的无机层（例如 ZnF ₂ 、 Zn ₃ N ₂ 、ZnSO ₃ 、ZnS、ZnO）内层提供优异的结构完整性，阻止水和 ZMA 的直接接触。此外，所形成的SEI具有高压缩模量（23.5 GPa），足以承受极端应力，例如枝晶刺穿。扫描电化学显微镜揭示了SEI的电子绝缘特性，可以促进其下方均匀的球形锌沉积。因此，具有梯度SEI的AZIB在20 mA cm ⁻² 和20 mA h cm ⁻² 的恶劣条件下实现了4100 h的超长循环稳定性，41的超高累积容量Zn‖NaV ₃ O ₈ 电池的平均库伦效率为 99.8%，具有 1 h cm ⁻² 的优异可逆性和 11 000 次循环寿命。

更新日期：2023-12-05

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