Introducing Artificial Solid Electrolyte Interphase onto the Anode of Aqueous Lithium Energy Storage Systems

Abstract

Aqueous lithium energy storage systems (ALESSs) offer several advantages over the commercially available nonaqueous systems, and the most noteworthy is that ALESSs have higher ionic conductivity, can be used safely, and are environmental-friendly in nature. The ALESS, however, exhibits faster capacity fading than their nonaqueous counterparts after repeated cycles of charge and discharge, thus limiting their wide-range applications. Excessive corrosion of metallic anodes in the aqueous electrolyte and accelerated growth of dendrites during the charge-discharge process are found to be the main reasons that severely impact the life span of ALESSs. Here, we introduce ultrathin graphene films as an artificial solid electrolyte interface (G-SEI) on the surface of a zinc anode to improve the cycling stability of an aqueous lithium battery system. The G-SEI is fabricated at different thicknesses and areas ranging from ∼1 to 100 nm and ∼1 to 10 cm, respectively, via a Langmuir-Blodgett trough method and deposited onto the surface of the zinc anode. Electrochemical characterizations show a significant reduction in corrosion current density (0.033 mA cm vs 1.046 mA cm for the control), suppression of dendritic growth (∼50%), and reduction in charge-transfer resistance (222 Ω vs 563 Ω for the control) when the G-SEI is utilized. The aqueous battery system with the G-SEI (100 nm thickness) on the anode exhibits ∼17% improvement in cycling stability (82% capacity retention after 300 cycles) compared to the control system. Comprehensive microscopy and spectroscopy characterizations reveal that the G-SEI not only controls the ion transport between the electrolyte and the anode surface (lower corrosion) but also promotes a uniform deposition (less dendritic growth) of zinc on the anode.

Ultrastable Zinc Anodes Enabled by Anti-Dehydration Ionic Liquid Polymer Electrolyte for Aqueous Zn Batteries

“…The corrosion potential of the Zn anode with IL-PAM (−0.776 V) is higher than the other two Zn electrodes in the LE and PAM (−1.019 and −1.004 V, respectively), as listed in Table S1. The more positive corrosion potential suggests the less tendency of the corrosion reaction. ,− More importantly, the corrosion current of the Zn anode in IL-PAM (0.044 mA cm –2 ) is only 1/12 of that in PAM (0.511 mA cm –2 ) and 1/25 of that in the LE (1.147 mA cm –2 ). The above linear polarization results indicate that the electrochemical stability of the Zn anode in IL-PAM is much higher.…”

“…The ex situ X-ray diffraction (XRD) results (Figure d) further demonstrate that the negative side reaction between the Zn anode and IL-PAM is hard to happen. Sharp peaks at around 8.09°, corresponding to the partially irreversible phase of (Zn­(OH 2 )) 3 (ZnSO 4 )­(H 2 O) 5 , are observed in the XRD results of Zn anodes in contact with the other two electrolytes. ,, The electrochemical stability of Zn anodes in different electrolytes was analyzed by linear polarization experiments (Figure e). The corrosion potential of the Zn anode with IL-PAM (−0.776 V) is higher than the other two Zn electrodes in the LE and PAM (−1.019 and −1.004 V, respectively), as listed in Table S1.…”

Recent Applications of Langmuir–Blodgett Technique in Battery Research

“…These factors led to enhanced cycling stability of the cathode materials. More recently, the same group applied these SEI engineering principles to zinc anode in an aqueous lithium battery system to improve the battery cycling stability . The graphene-based SEI on zinc anode led to reduced corrosion current density, suppressed dendrite growth, and uniform zinc deposition.…”

Fabrication of Zinc Anodes for Aqueous Lithium‐Ion Batteries by Supersonic Cold Spraying

“…The apparent higher surface area of supersonic zinc anode suggests that the supersonic zinc anode provides approximately 40 % higher surface area than the planar anode. [20][21][22] During the CA test, and charging of aqueous hybrid batteries, zinc ions deposit non-uniformly on the zinc anode surface which leads to the formation of sharp zinc dendrites. It is appropriate to assume Wenzel's model in this contact angle measurements since the magnitude of a water droplet (in mm range) is much larger than the roughness scale of the samples (in μm range).…”

“…After the initial transient drop in current densities of planar and supersonic zinc anodes (t~170 ms), the current density of the planar zinc anode declines more rapidly than that of the supersonic zinc anode, suggesting that planar anode undergoes a more dendritic growth than the supersonic anode . [20][21][22] During the CA test, and charging of aqueous hybrid batteries, zinc ions deposit non-uniformly on the zinc anode surface which leads to the formation of sharp zinc dendrites. [23] The growth of these dendrites are detrimental to the battery operation since this growth can lead to battery capacity fading and failure.…”