Enabling Highly Reversible Zn Anode by Multifunctional Synergistic Effects of Hybrid Solute Additives

Abstract

Aqueous zinc ion batteries are promising secondary batteries for next-generation electrochemical energy storage. In this work, we report a hybrid electrolyte system with 3 M Zn(OTf)2 as zinc salt and 1 M urea + 0.3 M LiOAc as hybrid solute additives for highly reversible aqueous zinc ion batteries. In this electrolyte system, partial coordinated water molecules of Zn2+ are replaced, and the original hydrogen bond network of the bulk electrolyte also suffers from interruption. Moreover, the introduction of lithium acetate solves the aggravated self-corrosion caused by urea on the one hand and inhibits the growth of dendrites through the electrostatic shielding effect on the other. Benefiting from this multifunctional synergistic effect, dendrite-free Zn plating/stripping for 600 h at 4.8 mA cm–2 (20% depth of discharge) and highly reversible plating/stripping at ∼99.7% Coulombic efficiency with a high cumulative plating capacity of 1600 mAh is achieved.

Review of regulating Zn2+ solvation structures in aqueous zinc-ion batteries

“…Organic small molecules are used not only as co-solvents, but also as functional additives in aqueous electrolytes for ZIBs. Their working mechanisms include regulating Zn deposition by absorbing on the surface of Zn anode, breaking the original H-bonds and/or in situ construction of SEI by participation of solvation structures of Zn 2+ [18,65,[70][71][72][73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89]. In this section, we mainly focused on the manipulation of solvation structures by adoption of functional additives.…”

“…% SL not only enabled stable cycling of Zn||Cu and Zn||Zn cells, but also endowed Zn||V 2 O 5 cells with a high capacity retention of 87.1% after 5000 cycles [79]. Besides, other organic small molecules such as 1,4-dioxane (DX) [70], vanillin [71] urea, LiOAC [72], thiourea (TU) [75,85], glucose [77], 15-crown-5 ether (15-CE-5) [80], phytic acid (PA) [82], hexaoxacyclooctadecane (18C6) [83], tranexamic acid (TXA) [84], threonine (TH) [87], diethyl ether (Et 2 O) [88], acetone [90], and etc. have been investigated, and their effect on the performance of ZIBs have been summarized in table 1.…”

From atomic modification to structure engineering: layered NiCo–MnO2 with ultrafast kinetics and optimized stress distribution for aqueous zinc ion storage

“…These unique properties make ZIBs one of the most promising technologies for future power grid energy storage. [6][7][8][9] To obtain more competitive ZIBs, using suitable cathode materials with outstanding capacity and stability is vital. Mn-based materials, [10][11][12] Prussian blue analogs (PBAs), [13][14][15] V-based materials, [16][17][18][19][20] and organic-based materials [21][22][23] are promising cathode materials for ZIBs.…”

“…The introduction of heteroatoms, particularly transition metal elements, has been proven to be an effective approach for improving the electronic conductivity of MnO 2 and boosting reaction kinetics. 9 The incorporation of transition metal ions not only improves the electronic conductivity of MnO 2 but also suppresses irreversible lattice distortion and manganese oxide dissolution. [36][37][38] To date, the effect of d-MnO 2 modication with transition metal ions and the associated reaction mechanism have remained elusive.…”

Competitive Solvation-Induced Interphases Enable Highly Reversible Zn Anodes

“…Besides, when the current density is turned back to 0.5 mA cm −2 , the Zn cell using the ZnOTF/MAAC electrolyte still works but delivers a lower overpotential, which can be explained by the decreased local current densities due to the surface structural change after cycling at higher current densities, which is commonly observed in both aqueous zinc metal batteries and nonaqueous lithium metal batteries. 8,34,35 However, the cell in ZnOTF does not operate, further proving the beneficial effect of MAAC as an ionic additive to significantly inhibit the dendrite growth upon Zn plating and enable high reversibility at high current density.…”