High-Rate and Long-Cycle Stability with a Dendrite-Free Zinc Anode in an Aqueous Zn-Ion Battery Using Concentrated Electrolytes

Abstract

Recently, metallic zinc (Zn) is becoming a promising ideal anode material for rechargeable aqueous batteries by providing high theoretical capacity (820 mA h/g) with divalent reaction, environmental friendliness, earthy abundance, low cost, low toxicity, higher water compatibility, and low electrochemical potential (−0.762 V vs SHE). However, intensive growth of zinc dendrites while plating/stripping lowers its coulombic efficiency and shortens the cycle life of the rechargeable devices. Here, we report a concentrated aqueous electrolyte (4.2 M ZnSO4 + 0.1 M MnSO4) with improved cycling stability of zinc metal anode achieving an average coulombic efficiency (ACE) ∼99.21% cycling for more than 1000 h at 0.2 mA/cm2 current density using a Zn||Cu cell. However, a frequently used diluted electrolyte (2 M ZnSO4 + 0.1 M MnSO4) only produces ACE ≈ 97.54% with a relatively short life cycle. The developed concentrated electrolyte with strongly aggregated ion pairs shows the synergetic effects of the enhanced solvation/desolvation process, electrostatic shielding, and Le Chatelier’s principle. Consequently, the additives simultaneously suppress Zn dendrites and dissolution of Mn2+ ions from the MnO2 cathode. A highly stable and reversible Zn||MnO2 cell retaining about 88.37% retention capacity was obtained after cycling for more than 1200 cycles at 938 mA/g current density.

Stress‐Release Functional Liquid Metal‐MXene Layers toward Dendrite‐Free Zinc Metal Anodes

“…A stable cyclic life up to 600 h ( Figure 4 a) has been achieved by the ZnGaIn//MXene symmetric cell tested at a current density of 1.0 mA cm −2 with the capacity of 1.0 mAh cm −2 , superior to those of ZnGaIn//Ti (150 h) and Zn foil (80 h) anodes and reported Zn‐based hybrid anodes (200−500 h). [ 29–31 ] This cyclic property is close to that of Zn anode modified by pH tuning strategy (600 h at 3 mA cm –2 ). [ 32 ] Even after 600 h (Figure 4a), ZnGaIn//MXene anode still exhibits a low mass‐transfer‐controlled overpotential (≈25 mV).…”

Stress‐Release Functional Liquid Metal‐MXene Layers toward Dendrite‐Free Zinc Metal Anodes

“…A stable cyclic life up to 600 h ( Figure 4 a) has been achieved by the ZnGaIn//MXene symmetric cell tested at a current density of 1.0 mA cm −2 with the capacity of 1.0 mAh cm −2 , superior to those of ZnGaIn//Ti (150 h) and Zn foil (80 h) anodes and reported Zn‐based hybrid anodes (200−500 h). [ 29–31 ] This cyclic property is close to that of Zn anode modified by pH tuning strategy (600 h at 3 mA cm –2 ). [ 32 ] Even after 600 h (Figure 4a), ZnGaIn//MXene anode still exhibits a low mass‐transfer‐controlled overpotential (≈25 mV).…”

A Reversible Anodizing Strategy in a Hybrid Electrolyte Zn-Ion Battery through Structural Modification of a Vanadium Sulfide Cathode

“…The MVS2 cathode has a deformed flower-like morphology due to the formation of new phases caused by Zn 2+ ion insertion/extraction. , Figure i shows that the morphological roughness of the Zn anode increases after 5000 GCD cycles. Such a roughened structure would promote Zn dendrite formation and accelerate the uneven nucleation and capacity fading. , The electrochemical performance of the recently reported vanadium-based cathode materials is compared with the present work and summarized in Table S2 . These findings suggest that the Mn-doped VS 4 cathode materials can be utilized for the fabrication of high-performance ZiBs.…”

Active Materials for Aqueous Zinc Ion Batteries: Synthesis, Crystal Structure, Morphology, and Electrochemistry

“…420 For example, if increasing the concentration of ZnSO 35a and b). 173 This indicates the impact of salt concentration on the solvation chemistry, especially the structure and composition of the solvation shell, and confirms the role of concentrated electrolytes on suppressing the water activity and hence the water-related side reactions. Since hydration number and hydrated cation radius will be smaller in a lower water content environment, the intercalation/deintercalation of hydrated Zn ions into the cathode materials is easier and faster in the concentrated aqueous electrolytes than the diluted ones.…”

Stress‐Release Functional Liquid Metal‐MXene Layers toward Dendrite‐Free Zinc Metal Anodes

“…A stable cyclic life up to 600 h ( Figure 4 a) has been achieved by the ZnGaIn//MXene symmetric cell tested at a current density of 1.0 mA cm −2 with the capacity of 1.0 mAh cm −2 , superior to those of ZnGaIn//Ti (150 h) and Zn foil (80 h) anodes and reported Zn‐based hybrid anodes (200−500 h). [ 29–31 ] This cyclic property is close to that of Zn anode modified by pH tuning strategy (600 h at 3 mA cm –2 ). [ 32 ] Even after 600 h (Figure 4a), ZnGaIn//MXene anode still exhibits a low mass‐transfer‐controlled overpotential (≈25 mV).…”

A Reversible Anodizing Strategy in a Hybrid Electrolyte Zn-Ion Battery through Structural Modification of a Vanadium Sulfide Cathode

“…The MVS2 cathode has a deformed flower-like morphology due to the formation of new phases caused by Zn 2+ ion insertion/extraction. , Figure i shows that the morphological roughness of the Zn anode increases after 5000 GCD cycles. Such a roughened structure would promote Zn dendrite formation and accelerate the uneven nucleation and capacity fading. , The electrochemical performance of the recently reported vanadium-based cathode materials is compared with the present work and summarized in Table S2 . These findings suggest that the Mn-doped VS 4 cathode materials can be utilized for the fabrication of high-performance ZiBs.…”

Active Materials for Aqueous Zinc Ion Batteries: Synthesis, Crystal Structure, Morphology, and Electrochemistry

“…420 For example, if increasing the concentration of ZnSO 35a and b). 173 This indicates the impact of salt concentration on the solvation chemistry, especially the structure and composition of the solvation shell, and confirms the role of concentrated electrolytes on suppressing the water activity and hence the water-related side reactions. Since hydration number and hydrated cation radius will be smaller in a lower water content environment, the intercalation/deintercalation of hydrated Zn ions into the cathode materials is easier and faster in the concentrated aqueous electrolytes than the diluted ones.…”

Stress‐Release Functional Liquid Metal‐MXene Layers toward Dendrite‐Free Zinc Metal Anodes

“…A stable cyclic life up to 600 h ( Figure 4 a) has been achieved by the ZnGaIn//MXene symmetric cell tested at a current density of 1.0 mA cm −2 with the capacity of 1.0 mAh cm −2 , superior to those of ZnGaIn//Ti (150 h) and Zn foil (80 h) anodes and reported Zn‐based hybrid anodes (200−500 h). [ 29–31 ] This cyclic property is close to that of Zn anode modified by pH tuning strategy (600 h at 3 mA cm –2 ). [ 32 ] Even after 600 h (Figure 4a), ZnGaIn//MXene anode still exhibits a low mass‐transfer‐controlled overpotential (≈25 mV).…”

A Reversible Anodizing Strategy in a Hybrid Electrolyte Zn-Ion Battery through Structural Modification of a Vanadium Sulfide Cathode

“…The MVS2 cathode has a deformed flower-like morphology due to the formation of new phases caused by Zn 2+ ion insertion/extraction. , Figure i shows that the morphological roughness of the Zn anode increases after 5000 GCD cycles. Such a roughened structure would promote Zn dendrite formation and accelerate the uneven nucleation and capacity fading. , The electrochemical performance of the recently reported vanadium-based cathode materials is compared with the present work and summarized in Table S2 . These findings suggest that the Mn-doped VS 4 cathode materials can be utilized for the fabrication of high-performance ZiBs.…”

Active Materials for Aqueous Zinc Ion Batteries: Synthesis, Crystal Structure, Morphology, and Electrochemistry

“…420 For example, if increasing the concentration of ZnSO 35a and b). 173 This indicates the impact of salt concentration on the solvation chemistry, especially the structure and composition of the solvation shell, and confirms the role of concentrated electrolytes on suppressing the water activity and hence the water-related side reactions. Since hydration number and hydrated cation radius will be smaller in a lower water content environment, the intercalation/deintercalation of hydrated Zn ions into the cathode materials is easier and faster in the concentrated aqueous electrolytes than the diluted ones.…”