『水系锌电』山东大学杨剑教授:超高倍率长寿命水系电池-Zn负极人工界面层的合理筛选

研究背景

锌枝晶、副反应和析氢等问题严重阻碍了水系锌金属(AZMBs)电池的实际应用，而这些问题都与锌金属与电解液的界面息息相关。因此，设计合理的界面是稳定锌负极的有效策略。目前，大量的研究发现构筑致密坚韧的SEI层可以有效保护锌负极，避免锌枝晶和析氢。然而，原位形成的SEI层通常无法承受电极的大的体积膨胀，因此事先构筑一层致密的SEI层成为一条可靠途径。虽然已经有不少的SEI材料被报道，如ZnO，ZnS，ZnSe，ZnF₂等，但是这种逐一试错实验不仅耗时费力，更可能错过最有潜力的SEI材料。因此，建立一套合理的SEI材料筛选方法显得尤为重要。

由此，山东大学杨剑教授团队从枝晶抑制能力和电荷转移特性这两个角度提出了一种筛选锌负极上潜在SEI的可行方法。为验证该筛选策略的有效性，Zn₃(BO₃)₂(ZBO)被首次报道。在对称电池中，Zn@ZBO在50 mA cm^-2的超高电流密度下和10 mAh cm^-2的大面积容量循环超过250小时。在贫电解质条件(10 μL mAh^-1)、有限的锌负极(N/P 比= 2.3)和高面积容量(5.0 mAh cm^-2)等严苛的测试条件下，Zn@ZBO||MnO₂全电池展示了令人印象深刻的累积容量(~406 mAh cm^-2)。这项工作的意义不仅在于ZBO对Zn的首次报道表现出优异的电化学性能，而且还在于为筛选其他金属负极有前景的SEI材料提供了一条可行的途径。

其成果以题为“Rational Screening of Artificial Solid Electrolyte Interphases on Zn for Ultrahigh-Rate and Long-Life Aqueous Batteries”在国际知名期刊Advanced Materials上发表。本文第一作者为山东大学博士后汪冬冬，通讯作者为山东大学杨剑教授，通讯单位为山东大学化学与化工学院。

研究亮点

⭐不同于以前的试错方法，本文以枝晶抑制能力和电荷转移性能为指标，成功建立了一套合理、高效的锌负极SEI材料筛选方案。

⭐选择ZBO作为模型，从实验和理论上验证了该筛选策略的有效性。这项工作不仅是ZBO作为先进锌负极人工界面层的第一篇报道，而且为有类似问题的金属负极筛选有前途的SEI材料提供了一种可操作的方法。

⭐Zn@ZBO负极展示了优异的电化学性能。即使是在低含量电解液(E/C =10 μL mAh^-1)，有限的锌负极(N/P = 2.3)和5.0 mAh cm^-2的高面积容量下，Zn@ZBO||MnO₂全电池仍然表现出出色的循环性能和令人印象深刻的累积容量。

图文导读

Figure 1 Theoretical screening of promising SEI materials. (a) The core elements of an ideal SEI material on Zn; (b, c) Schematic illustration about (b) charge-transfer properties and (c) dendrite-suppressing ability; (d) band gaps and shear moduli of potential SEI candidates; (e) energy barriers of Zn²⁺diffusion on ZHS, ZnO, ZnF₂, Zn₃(PO₄)₂and ZBO; (f) Zn diffusion pathway at the interfaces of Zn@ZHS, Zn@ZnO, Zn@ZnF₂, Zn@Zn₃(PO₄)₂and Zn@ZBO and (g) the corresponding energy barriers at the interfaces; (h) interface structure, interfacial energy (γ) and Young’s modulus (E) of Zn@ZBO, (i) dendrite suppression ability (γE) of Zn@ZHS, Zn@ZnO, Zn@ZnF₂, Zn@Zn₃(PO₄)₂and Zn@ZBO. Zn, O, H, S, B, F and P atoms are shown in gray/blue, red, pink, yellow, green, orange and blue-green, respectively.

Figure 2 The preparation process and structure/composition characterization of Zn@ZBO. (a) Schematic illustration on the synthesis of Zn@ZBO; (b) Top-view SEM images of Zn@ZBO; (c) XRD patterns of bare Zn and Zn@ZBO; (d-f) XPS spectra of (d) Zn 2p, (e) B 1s and (f) O 1s of Zn@ZBO;(g)surface mapping and (h) spatial distribution of ZnBO₃^- and BO₂^-on Zn@ZBO detected by ToF-SIMS.

Figure 3Uniform plating/stripping of Zn on Zn@ZBO. Ex-situ SEM images of (a-b) bare Zn and (c-d) Zn@ZBO after the 1^st plating at a current density of 2 mA cm^-2 for a capacity of 10 mAh cm^-2; SEM images of (e-f) bare Zn and (g-h) Zn@ZBO after 100 cycles; AFM imagesof Zn deposition on (i) bare Zn and (j) Zn@ZBO; COMSOL simulation of the morphology evolution of (k) bare Zn and (l) Zn@ZBO during Zn plating process.

Figure 4 ZBO promotes the reaction kinetics and reduces the side reactions. (a) Voltage profiles of bare Zn and Zn@ZBO at a current density of 5 mA cm^-2; (b) CV curves of Zn plating/stripping on bare Zn and Zn@ZBO; (c) Arrhenius curves and activation energies of Zn²⁺ deposition on bare Zn or Zn@ZBO in the symmetric cells; (d) adsorption energy of H₂O on different crystals and the corresponding structures; (e) In-situ optical microscopic images of the Zn plating on bare Zn and Zn@ZBO at a current density of 10 mA cm^-2; (f) LSV curves and (g) LP curves of bare Zn and Zn@ZBO;(h) spatial distributionof ZnSO₄OH^- formed on bare Zn and Zn@ZBOafter 100 cycles viewed by ToF-SIMS; (i) XRD patterns of bare Zn and Zn@ZBO after 100 cycles; (j) The dissociation energy barriers of H₂O on the bare Zn and Zn@ZBO;the corresponding initial state (IS), transition state (TS), and final state (FS) structures are shown in the inset.

Figure 5 The electrochemical performance of Zn anodes. (a) Rate performance and (b) voltage hysteresis of the symmetric cells using bare Zn or Zn@ZBO; (c, d) Cycling performance of the symmetric cells using bare Zn and Zn@ZBO (c) at a current density of 60 mA cm^-2 for a capacity of 2 mAh cm^-2 or (d) at a current density of 50 mA cm^-2for a capacity of 10 mAh cm^-2; (e) Comparison of the cumulative capacity and the product of the largest current density and areal capacity of symmetric cells with the previous reports; (f, g) CE of Zn plating/stripping on Cu and Cu@ZBO (f) at30 mA cm^-2 for a capacity 1 mAh cm^-2; or (g) at 20 mA cm^-2 for a capacity 10 mAh cm^-2; the insets are corresponding voltage profiles of the asymmetric cells; (h) Comparison of the asymmetrical cells with previous reports in cycle number and current density.

Figure 6 The electrochemical performance of Zn||MnO₂ full cells. (a) Rate performance, (b) Cycling performance and Coulombic efficiencies (CEs) of the full cells using either bare Zn or Zn@ZBO as the anode at 10 C (1C = 308 mA g^-1); (c, d) Self-discharge tests of the full cells after a rest of 48 h; (e) Cycling performance and CEs of the full cells with N/P (Negative/Positive Electrode Capacity) of 2.3 and E/C (Electrolyte/Capacity) of 10 μL mAh^-1; (f) Comparison of our performance with the previous reports; (g) Cycling performance and (h) Optical images of the pouch cells usingbare Zn or Zn@ZBO as the anode. 

研究结论

综上所述，本文以枝晶抑制能力和电荷转移性能为指标，成功建立了一套合理、高效的锌负极SEI材料筛选方案。选择ZBO作为模型，从实验和理论上验证了该筛选策略的有效性。ZBO对Zn具有较高的界面能和较大的杨氏模量，极大地抑制了Zn枝晶的形成。ZBO具有低的Zn²⁺扩散势垒，有利于锌离子在界面和表面的传输。因此，使用Zn@ZBO的对称Zn||Zn电池展现了较长的循环寿命(在50 mA cm^-2和容量为10 mAh cm^-2下循环250小时)，锌的利用率高达60%。即使是在低电解质(E/C = 10 μL mAh^-1)，有限的锌含量(N/P = 2.3)和5.0 mAh cm^-2的高面积容量下，Zn@ZBO||MnO₂全电池仍然表现出出色的循环性能和令人印象深刻的累积容量。这项工作不仅是ZBO作为先进锌阳极人工层的首次报道，而且为具有类似问题的金属阳极筛选有前途的SEI材料提供了一种可操作的方法。

文献信息

Dongdong Wang，Hongxia Liu，Dan Lv，Cheng Wang，Jian Yang*，Yitai Qian, Rational Screening of Artificial Solid Electrolyte Interphases on Zn for Ultrahigh-Rate and Long-Life Aqueous Batteries, Adv. Mater.

https://doi.org/10.1002/adma.202207908

通讯作者简介

杨剑，山东大学化学与化工学院教授，博士生导师。国家自然科学奖，国务院政府特殊津贴，山东省泰山学者特聘教授。结合化学和材料应用的基础研究，瞄准国际前沿方向和国家能源战略需求的核心关键问题开展工作。以通讯作者在Angew. Chem. Int. Ed., Adv. Mater., Adv. Energy Mater., ACS Nano., Adv. Funct. Mater.,等知名国际刊物上发表多篇学术论文，累计引用次数12000+，H=61 (数据来源：Web of Science)。其中，多篇论文MaterialsViewChina.com, Chemeurope.com, VerticalNews, X-mol. com等国内外网站作为研究亮点进行专题报道。多篇论文被Web of Science 网站评选为ESI Highly Cited Papers。

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