Decoupling, quantifying, and restoring aging-induced Zn-anode losses in rechargeable aqueous zinc batteries

Colossal Capacity Loss during Calendar Aging of Zn Battery Chemistries

“…This observed degradation suggests the dissolution of Zn 2+ products from corrosion and implies an additional loss of active material during calendar aging. This is in good agreement with reported X-ray diffraction (XRD) results after calendar aging indicating the formation of Zn(OH) 2 and ZnSO 4 [Zn(OH) 2 ] 3 •xH 2 O (ZHS) 26 and also in stark contrast to previous mechanisms of CE loss in Li-based batteries, where the presence of a conformal SEI passivation layer can prevent uninhibited corrosion during calendar aging. 17,19,35,41 Without an SEI layer to effectively passivate Zn metal, corrosion occurs continuously during calendar aging and is coupled to dead Zn formation.…”

“…3c). Importantly, this continuous and rapid aging behavior, whether at low (1 mA cm −2 ) or high current density (10 mA cm −2 ), 26 is completely distinct from all other Li-based battery chemistries, as the capacity loss during aging in Li-ion anodes (i.e., graphite, Si, Li metal) levels off as the SEI layer becomes more passivating as it thickens during aging. 6 Finally, the CE loss percentage appears to decrease with the increasing deposition capacity of metallic Zn (Figure 2e, Supplementary Fig.…”

“…We perform TGC on electrochemically stripped Zn−Cu half-cells after 24 h aging in a diverse range of electrolyte chemistries and reveal that the large majority of CE loss comes from dead Zn (rather than corrosion) in the form of Zn 0 , which is consistent with our XPS results. Figure 5d 26 ) and elucidates potential design principles to mitigate their impact. Mitigation Strategies.…”

“…Recently, Pu et al explored the Zn-anode losses that occur during calendar aging. Indeed, the capacity loss was shown to form in only one specific system: Zn/Ti half-cells with mildly acidic 2 M zinc sulfate (ZnSO 4 ) as the electrolyte . Furthermore, the few calendar aging studies on Zn-based anodes involving full-cells primarily examined capacity losses with Zn-excess full-cells, which failed to isolate the effects of anode and cathode on aging. ,− Therefore, the detailed aging mechanism of the metallic Zn anode remains elusive, representing a key gap in our systematic understanding of Zn battery chemistry.…”

Biphasic Electrolyte Engineering Enabling Reversible Zn Metal Batteries

“…Therefore, the aging-induced "screened Zn" is believed to be a major contributor to capacity fade. 51 The storage properties of the full cells using different electrolytes were investigated. After a rest of 7 days, the cell using 1 M ZnSO 4 electrolyte exhibits dramatic deterioration of the cycling performance (Figure 5f).…”