Joule

Joule

Volume 4, Issue 4, 15 April 2020, Pages 771-799
Journal home page for Joule

Review
Scientific Challenges for the Implementation of Zn-Ion Batteries

https://doi.org/10.1016/j.joule.2020.03.002Get rights and content
Under an Elsevier user license
open archive

Context & Scale

Looming concerns of climate change and the prospects of sustainable energy resources, such as solar and wind, have entered the global spotlight, triggering the hunt for reliable, low-cost electrochemical energy storage. Among the various options, lithium-ion batteries (LIBs) are currently the most attractive candidates because of their high energy density and foothold in the marketplace. However, many factors (expense, safety, and lifetime) will likely limit their large-scale applications and dictate against their use in stationary electrochemical energy storage (grid, mini-grids, telecommunication stations, etc.) wherein low cost and durability are more of a concern than weight. Alternative battery technologies are thus of considerable current interest. These include Zn-ion batteries (that utilize a Zn metal negative electrode), which offer greater safety, environmental friendliness, and affordability compared with their Li-ion cousins.

There has been an explosion of research in this field over the past few years—resulting in a plethora of publications—but clarity on the fundamental aspects of Zn-battery function in both aqueous and non-aqueous media is yet to be achieved. In this review, we provide a broad yet balanced overview of the field, insights into important progress made to date, key challenges to be overcome in future research, and perspectives on the many open questions remaining. In particular, we critically analyze the problem of proton co-intercalation in aqueous media and address the challenges it imposes on the practical implementation of Zn-ion technology for large-scale applications. We question whether Zn-ion intercalation (i.e., diffusion in the bulk) or pseudocapacitive behavior underlies some ultra-high rates that have been reported in aqueous electrolytes and note that the surprisingly good performance of some cathode materials in non-aqueous cells bodes well for future development.

Summary

The safety, affordability, and impressive electrochemical performance of many Zn-ion batteries (ZIBs) has recently triggered an overwhelming literature surge. As is typical for a new area, initial enthusiasm and high expectations have now been replaced by a more measured period of research that reaches deep into the underlying factors controlling electrochemical properties. Rather than battery metrics, this review focuses on fundamental aspects of the chemistry of ZIBs that are the least understood and on which there has been progress over the last few years. We provide guidance for future research regarding (1) the significant challenge of proton/Zn2+ co-intercalation in aqueous media, (2) limitations to conversion chemistry that often accompanies ZIB electrochemistry, (3) positive aspects of facile Zn2+ (de)intercalation in nonaqueous electrolytes and organic cathode materials, (4) the desolvation penalty at electrode-electrolyte interfaces, (5) solutions for controlling Zn dendritic growth, and (6) suggested electrochemistry protocols for the field.

Keywords

Zn-ion battery
stationary electrochemical energy storage
Zn intercalation

Cited by (0)

3

These authors contributed equally

© 2020 Published by Elsevier Inc.