Stabilizing Zinc Anodes by a Uniform Nucleation Process with Cysteine Additive

Creatinine: A Muscle Metabolite as a Multifunctional Electrolyte Additive for Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries (AZIBs) have demonstrated considerable potential for utilization in large-scale energy storage applications, driven by their environmental sustainability, inherent safety and cost-effectiveness. Nonetheless, the growth of Zn dendrites and side reactions, resulting in degraded cycling stability, poses a substantial obstacle to the practical implementation of AZIBs. Herein, it is demonstrated that creatinine (Cre), a metabolite derived from muscle, serves as a multifunctional electrolyte additive that enhances the performance of AZIBs. Both experimental and theoretical analyses reveal that Cre, when used as an electrolyte additive, fulfills three key roles: it disrupts the solvation structure of Zn2+ by carbonyl group; it forms a water-deficient electric double layer, thereby reducing the likelihood of interfacial water decomposition; and it promotes the deposition of Zn2+ on the (002) planes, facilitating the uniform deposition. The Zn||Zn symmetric cell utilizing a 1 M ZnSO4 electrolyte with the addition of 0.3 M Cre exhibits stable cycling for 900 h under the condition of 1 mA cm-2 and 1 mAh cm-2, representing an over 11-fold increase in lifespan. Furthermore, the Zn||VO2 full cell demonstrates a capacity retention of ≈105 mAh g-1 after 300 cycles at a rate of 10 C.

Nano-Zinc Sulfide Modified 3D Reconstructed Zinc Anode with Induced Deposition Effect Assists Long-Cycle Stable Aqueous Zinc Ion Battery

Aqueous zinc ion batteries are often adversely affected by the poor stability of zinc metal anodes. Persistent water-induced side reactions and uncontrolled dendrite growth have seriously damaged the long-term service life of aqueous zinc ion batteries. In this paper, it is reported that a zinc sulfide with optimized electron arrangement on the surface of zinc anode is used to modify the zinc anode to achieve long-term cycle stability of zinc anode. The effective active sites of the zinc metal anode surface are first significantly improved by a simple ultrasound-assisted etching strategy, and then the in situ zinc sulfide interface phase further guides the zinc ion deposition behavior on the surface of the zinc metal anode. The zinc sulfide protective layer well regulates the interfacial electric field and the migration of Zn2+, thereby significantly promoting the homogenization of zinc ion flux to achieve dendrite-free deposition. In addition, the aqueous zinc ion full cell assembled based on ZnS@3D-Zn anode achieves better output performance in long-term cycles. In summary, this work sheds light on the importance of reasonable interfacial modification for the development of dendrite-free and stable zinc anode chemistry, which opens up a new path for promoting the development of zinc-based batteries.

Interfacial double-coordination effect reconstructing anode/electrolyte interface for long-term and highly reversible Zn metal anodes

The highly reversible electrochemical deposition and dissolution of zinc metal anode is a critical feature for the practical application of aqueous zinc-ion batteries (ZIBs). Nevertheless, this process is seriously hindered by the uncontrollable electrodeposition and interfacial side reactions caused by thermodynamically unstable anode/electrolyte interface (AEI). Guided by the electrode/electrolyte interface chemistry, thiamine hydrochloride (TH) as a novel additive is added into traditional ZnSO4 (ZS) electrolyte to induce sustained reversible Zn deposition/stripping. Spectroscopic characterizations and electrochemical tests reveal that TH can adsorbed on the anode surface owning to the strong double-coordination effect between N, S atoms and Zn atoms via Zn-N and Zn-S chemical bonds. In addition, there are polar hydroxyl groups in the TH molecular structure which can form hydrogen bonds with water molecules. Thus, the adsorbed TH layer can not only guide the diffusion of Zn2+ ions and achieve dendrite-free electrodeposition process, but also prevent intimate contact between water and anode to suppress the occurrence of interface side reactions. Based on these benefits, the TH additive achieves an ultra-long stable cycle lifespan to 2045 h at 1 mA cm-2 and 1 mAh cm-2. Even at a higher current density of 5 mA cm-2, prolonged cycling performance about 773 h is demonstrated. Besides, the assembled Zn//NVO full cells reveal excellent capacity retention and rate performance under practical conditions, highlighting the efficient and reliable coordination effect of TH additive at the AEI.

Additives for Aqueous Zinc-Ion Batteries: Recent Progress, Mechanism Analysis, and Future Perspectives

Aqueous zinc-ion batteries (ZIBs) stand out as a promising next-generation electrochemical energy storage technology, offering notable advantages such as high specific capacity, enhanced safety, and cost-effectiveness. However, the application of aqueous electrolytes introduces challenges: Zn dendrite formation and parasitic reactions at the anode, as well as dissolution, electrostatic interaction, and by-product formation at the cathode. In addressing these electrode-centric problems, additive engineering has emerged as an effective strategy. This review delves into the latest advancements in electrolyte additives for ZIBs, emphasizing their role in resolving the existing issues. Key focus areas include improving morphology and reducing side reactions during battery cycling using synergistic effects of modulating anode interface regulation, zinc facet control, and restructuring of hydrogen bonds and solvation sheaths. Special attention is given to the efficacy of amino acids and zwitterions due to their multifunction to improve the cycling performance of batteries concerning cycle stability and lifespan. Additionally, the recent additive advancements are studied for low-temperature and extreme weather applications meticulously. This review concludes with a holistic look at the future of additive engineering, underscoring its critical role in advancing ZIB performance amidst the complexities and challenges of electrolyte additives.

Low-Cost Aqueous Electrolyte with MBA Additives for Uniform and Stable Zinc Deposition

Aqueous zinc ion batteries (AZIBs) are attracting increasing research interest due to their intrinsic safety, low cost, and scalability. However, the issues including hydrogen evolution, interface corrosion, and zinc dendrites at anodes have seriously limited the development of aqueous zinc ion batteries. Here, N,N-methylenebis(acrylamide) (MBA) additives with -CONH- groups are introduced to form hydrogen bonds with water and suppress H2O activity, inhibiting the occurrence of hydrogen evolution and corrosion reactions at the interface. In situ optical microscopy demonstrates that the MBA additive promotes the uniform deposition of Zn2+ and then suppresses the dendrite growth on the zinc anode. Therefore, Zn//Ti asymmetric batteries demonstrate a high plating/stripping efficiency of 99.5%, while Zn//Zn symmetric batteries display an excellent cycle stability for more than 1000 h. The Zn//MnO2 full cells exhibit remarkable cycling stability for 700 cycles in aqueous electrolytes with MBA additives. The additive engineering via MBA achieved the dendrite-free Zn anodes and stable full batteries, which is favorable for advanced AZIBs in practical applications.

Massively Reconstructing Hydrogen Bonding Network and Coordination Structure Enabled by a Natural Multifunctional Co-Solvent for Practical Aqueous Zn-Ion Batteries

The practical application of aqueous Zn-ion batteries (AZIBs) is hindered by the crazy Zn dendrites growth and the H2O-induced side reactions, which rapidly consume the Zn anode and H2O molecules, especially under the lean electrolyte and Zn anode. Herein, a natural disaccharide, d-trehalose (DT), is exploited as a novel multifunctional co-solvent to address the above issues. Molecular dynamics simulations and spectral characterizations demonstrate that DT with abundant polar -OH groups can form strong interactions with Zn2+ ions and H2O molecules, and thus massively reconstruct the coordination structure of Zn2+ ions and the hydrogen bonding network of the electrolyte. Especially, the strong H-bonds between DT and H2O molecules can not only effectively suppress the H2O activity but also prevent the rearrangement of H2O molecules at low temperature. Consequently, the AZIBs using DT30 electrolyte can show high cycling stability even under lean electrolyte (E/C ratio = 2.95 µL mAh-1), low N/P ratio (3.4), and low temperature (-12 °C). As a proof-of-concept, a Zn||LiFePO4 pack with LiFePO4 loading as high as 506.49 mg can be achieved. Therefore, DT as an eco-friendly multifunctional co-solvent provides a sustainable and effective strategy for the practical application of AZIBs.