Electrochemistry of Multilayer Electrodes: From the Basics to Energy Applications

Abstract

Metrics & MoreArticle Recommendations CONSPECTUS: Growing environmental concern has increased the demand for clean energy, and various technologies have been developed to utilize renewable energy sources. With the development of highly efficient energy conversion and storage systems, fundamental studies on the electrochemistry of electrodes are critical because the functionality of most of these systems relies on interfacial electrochemical reactions that occur on the surfaces of the electrodes. In this context, efficient electrode design methods are required to study specific electrochemical principles and the mechanisms of interfacial reactions on the surface of electrodes.Compared with other electrode fabrication methods, layer-by-layer (LbL) assembly is a simple, inexpensive, and versatile process for producing highly ordered multilayer thin-film electrodes from a diverse array of materials. LbL-assembled multilayer electrodes exhibit distinct electrochemical properties compared with electrodes created via other fabrication methods because of the nanoscale control of the composition and structures of electrodes afforded by LbL assembly. LbL assembly can generate unique nanoarchitectures from a multiplicity of electroactive components to investigate the detailed electrochemical mechanisms within the electrode, allowing for investigations of the internal-architecture-dependent electrochemical properties within the electrodes. As electrochemical LbL research has progressed over the last 10 years, our group has performed pioneering studies on the fundamental electrochemical properties of multilayer electrodes fabricated via LbL assembly for diverse energy applications. In this Account, we aim to outline the fundamental electrochemistry occurring at the nanoscale level on multilayer thin-film LbL electrodes using our work to illustrate these concepts, including the dependence of the electrochemistry on the thickness and architecture of multilayer electrodes, competition between mass and charge transfer, and control over the ionpermeation selectivity and interfacial dipole moments in multilayer electrodes. We anticipate that our approach to LbL-assembled electrodes will be of great interest and provide an attractive platform for the investigation of fundamental multilayer thin-film electrochemistry. We also believe that it will provide guidelines for research efforts toward future electrode engineering.

Layer-by-Layer Construction of a Nanoarchitecture by Polyoxometalates and Polymers: Enhanced Electrochemical Hydrogen Evolution Reaction

“…Previous research has also shown that increasing the number of layers increases the active surface area and active sites, so does the electrochemical behavior. 63 EIS is a reliable technique that is employed to investigate the charge-transfer mechanisms associated with the varying layer constructions. EIS was employed to measure the conductive properties of the PEI/[(TBA)Mo 12 (AleThio) 4 ] bilayers in 0.5 M H 2 SO 4 .…”

Emerging smart design of electrodes for micro‐supercapacitors: A review

“…The LbL process is a prevalent cyclic process that alternately deposits functional thin films of multiple materials onto various substrates with nanometer precision. 17 The LbL electrode offers many benefits: (ⅰ) providing hybrid thin films with a regular order, (ⅱ) balancing the requirements between improved mass loading and insufficient conductivity of thick electrodes without dead volume (Figure 3), [30][31][32][33] (ⅲ) exhibiting good compatibility with most deposition techniques, and (ⅳ) lowering the charge transfer resistance to enhance the rate capability. 18 Additionally, electrodes based on the LbL design show much popularity in the field of electronic miniaturization due to enormous advantages of thin-film technology, including the ease of material synthesis/deposition, the well-developed fabrication (such as patterning and lithography), and integration technique in the semiconductor field.…”

Scalable Dry-Pressed Electrodes Based on Holey Graphene

“…For the latter, composite electrodes with either sandwichlike or double-decker architectures were successfully fabricated and exhibited similar stable cycling performance at a high curtailing capacity (4 mAh cm –2 ). Such designed architectures may enable further mechanistic investigations into Li–O 2 electrocatalytic chemistry in thick electrodes …”

“…Such designed architectures may enable further mechanistic investigations into Li−O 2 electrocatalytic chemistry in thick electrodes. 48 Soluble catalysts, or redox mediators (RMs), were also explored with the high-mass-loading hG air cathode platform. 36 Unlike heterogeneous electrocatalysts which are typically metalcontaining compounds, the RMs are small ions or molecules that are soluble in the electrolyte and thus much more effective in accessing the insoluble discharge products to improve the charge reaction.…”