Diminishing Interfacial Turbulence by Colloid‐Polymer Electrolyte to Stabilize Zinc Ion Flux for Deep‐Cycling Zn Metal Batteries

Abstract

volumetric capacity of 5855 mAh cm −3 ) of metallic Zn. [1] However, nonuniform Zn deposition aggravates formation of dendrites and leads to a low Coulombic efficiency (CE), resulting in battery performance deterioration. It is believed that regulated Zn 2+ distribution is beneficial to the uniform Zn plating. [1,2] Many works in the field of Zn anode realize uniform Zn 2+ distribution and improve Zn electrochemistry by constructing efficient Zn 2+ transport path. [1][2][3] However, we find that at deep cycling (high current densities and capacities), the interfacial turbulence is a severe problem that cannot be ignored to destroy the stability of Zn 2+ transport path. In details, the Zn 2+ ions flux distribution is affected by two factors: construction and stabilization of Zn 2+ transport path. Homogeneous Zn 2+ channels are helpful to realize uniform ion flux distribution; while Zn 2+ transport path would be destructed due to inevitable severe interfacial turbulence caused by fluidity of electrolyte and undesired H 2 evolution reaction (HER), which would lead to the disturbance of ion flux and uneven Zn deposition. In addition, the HER is usually accompanied by metal corrosion. [3] This not only consumes water in the electrolyte, but also the generated H 2 would result in swelling of the cell and even cell rupture. Meanwhile, the consumption of H + in water results in the accumulation of residual OH − ions, driving the corrosion reaction to form inactive Zn 4 SO 4 (OH) 6 •xH 2 O byproducts. [4,5] Moreover, the operation of ZMBs with high capacities is limited owing to the incomplete Zn discharging process because accumulated Zn leads to increased polarization of the battery; High current density can also cause an inhomogeneous electric field, incomplete metal stripping, and excessive polarization especially current and concentration polarization. [6,7] These issues can cause more serious interfacial instability and disturbance for deep-cycling batteries with high areal capacities and high current densities, significantly undermining the performance of ZMBs and plaguing their scale-up implementation. Aqueous deeply rechargeable Zn metal electrodes can only be achieved when the interfacial turbulence is rectified. Considering that free water molecules in electrolytes induce H 2 evolution and interfacial corrosion, highly concentrated The fluidity of aqueous electrolytes and undesired H 2 evolution reaction (HER) can cause severe interfacial turbulence in aqueous Zn metal batteries (ZMBs) at deep cycling with high capacities and current densities, which would further perturb ion flux and aggravate Zn dendrite growth. In this study, a colloid-polymer electrolyte (CPE) with special colloidal phase and suppressed HER is designed to diminish interfacial turbulence and boost deep Zn electrochemistry. Density functional theory calculations confirm that the quantitative migratory barriers of Zn 2+ along the transport pathway in CPE demonstrate much smaller fluctuations compared with normal aqueous electrolyte, indicating...

Engineering a self-adaptive electric double layer on both electrodes for high-performance zinc metal batteries

“…Those outstanding results are attributed to the suppressed hydrogen evolution reaction and dendrite growth by ImS additive. As proposed in previous reports, 50,51,54,55 the CE should comprehensively take the current density and capacity plated per cycle and cumulative plated capacity (CPC) into account. Therefore, Fig.…”

Developing Thermoregulatory Hydrogel Electrolyte to Overcome Thermal Runaway in Zinc‐Ion Batteries

“…In the BE (Figure S11a, Supporting Information), several hydrogen bubbles were produced and fluttered in disorder in the fluids, leading to excessive disturbance, instability, and inhomogeneity of Zn deposition. [33] For the BHE, the effect of dendrite inhibition was still unsatisfactory (Figure S11b, Supporting Information). In contrast, TRHE demonstrated a positive effect in inhibiting hydrogen evolution, enabling a uniform deposition of Zn and suppressing the growth of Zn dendrites (Figure S11c, Supporting Information).…”

Organosulfur polymer-based cathode materials for rechargeable batteries

“…Similarly, other in situ techniques such as Raman, XRD, and optical microscope, as a kind of powerful characterization methods, have also been successfully used in other research fields. 42–44 After that, they further copolymerized elemental sulfur with chain-like cis -1,4-polyisoprene (RUB) molecule at 159 °C to obtain highly cross-linked sulfur-rich vulcanized clay rubber (SRVCR), 45 as shown in Fig. 3d.…”