Nanoporous CaCO₃ Coatings Enabled Uniform Zn Stripping/Plating for Long‐Life Zinc Rechargeable Aqueous Batteries

Abstract

Zn‐based batteries are safe, low cost, and environmentally friendly, as well as delivering the highest energy density of all aqueous battery systems. However, the application of Zn‐based batteries is being seriously hindered by the uneven electrostripping/electroplating of Zn on the anodes, which always leads to enlarged polarization (capacity fading) or even cell shorting (low cycling stability). How a porous nano‐CaCO3 coating can guide uniform and position‐selected Zn stripping/plating on the nano‐CaCO3‐layer/Zn foil interfaces is reported here. This Zn‐deposition‐guiding ability is mainly ascribed to the porous nature of the nano‐CaCO3‐layer, since similar functionality (even though relatively inferior) is also found in Zn foils coated with porous acetylene black or nano‐SiO2 layers. Furthermore, the potential application of this strategy is demonstrated in Zn|ZnSO4+MnSO4|CNT/MnO2 rechargeable aqueous batteries. Compared with the ones with bare Zn anodes, the battery with a nano‐CaCO3‐coated Zn anode delivers a 42.7% higher discharge capacity (177 vs 124 mAh g−1 at 1 A g−1) after 1000 cycles.

Highly Reversible Zn Anode Enabled by Controllable Formation of Nucleation Sites for Zn‐Based Batteries

“…Surface coating layer on anode acts as a protective layer to decrease the contact area between electrode and electrolyte, suppressing the HER and Zn corrosion during cycling. Zhi's group developed a porous nano‐CaCO 3 coating to achieve uniform Zn stripping/plating, and it is also found that the Zn dendrites formation would be facilitated with increased current densities, where the electrohealing methodology can be expected to eliminate already‐formed dendrites 38,39. The electrolyte optimization positively influences the performance of Zn anode by forming a smooth absorbed layer or decreasing the active of H 2 O in the electrolyte, leading to the dendrite‐free anode and guaranteeing the long cycle life of battery.…”

“…Up till now, various strategies have been proposed to solve the above challenges, which are mainly involving electrodebased solutions, [29][30][31][32] electrolyte-based solutions, [33][34][35][36] and elaborate interface engineer. [37][38][39][40] As for example, Archer's group reported the exceptional reversibility of Zn, which is prepared by employing graphene with a low lattice mismatch for Zn under an epitaxial mechanism. [29] Surface coating layer on anode acts as a protective layer to decrease the contact area between electrode and electrolyte, suppressing the HER and Zn corrosion during cycling.…”

“…Zhi's group developed a porous nano-CaCO 3 coating to achieve uniform Zn stripping/plating, and it is also found that the Zn dendrites formation would be facilitated with increased current densities, where the electrohealing methodology can be expected to eliminate alreadyformed dendrites. [38,39] The electrolyte optimization positively influences the performance of Zn anode by forming a smooth absorbed layer or decreasing the active of H 2 O in the electrolyte, leading to the dendrite-free anode and guaranteeing the long cycle life of battery. Wang's group developed trimethyl phosphate/triethyl phosphate-based electrolytes, which enabled the dendrite-free Zn deposition with high Coulombic efficiency (CE) (>99%) and controllable Zn morphologies.…”

A Novel Dendrite‐Free Mn2+/Zn2+ Hybrid Battery with 2.3 V Voltage Window and 11000‐Cycle Lifespan

“…However, a series of intrinsic drawbacks including poor safety, environmental pollution derived from organic electrolytes as well as high cost from the scarce lithium resources remain challenges and hinder their in real energy storage systems. [14] Researchers have also proposed to suppress the growth of dendrites by constructing Zn anodes with a 3D structure. [15] However, its complex production processes and high production costs limit their wide applications.…”

A Long‐Life Battery‐Type Electrochromic Window with Remarkable Energy Storage Ability

“…During discharging, the blue‐colored PB coating is reduced into colorless and transparent PW by a K + and e − coinsertion reaction . At the same time, the Zn negative electrode loses its electrons and is electrochemically striped as Zn 2+ , to compensate the consumption of K + and e − by the cathodic reaction. In other words, this discharging reaction is also a spontaneous bleaching process with an electric energy output.…”