Michael A. Pope

• BEng & Biosci, MA, PhD
• Professor (Associate) at University of Waterloo

Graphene has been heralded as a promising electrode material for high energy and power density electrochemical supercapacitors. This is in spite of recent work confirming the low intrinsic capacitance of the graphene/electrolyte interface limited by graphene’s low quantum capacitance, an effect known for the basal-plane of graphite for over four de...

We use electrochemical impedance spectroscopy to measure the effect of diluting a hydrophobic room temperature ionic liquid with miscible organic solvents on the differential capacitance of the glassy carbon–electrolyte interface. We show that the minimum differential capacitance increases with dilution and reaches a maximum value at ionic liquid c...

Battery technologies involving Li-S chemistries have been touted as one of the most promising next generation systems. The theoretical capacity of sulfur is nearly an order of magnitude higher than current Li-ion battery insertion cathodes and when coupled with a Li metal anode, Li-S batteries promise specific energies nearly five-fold higher. Howe...

We contrast the performance of monolayer electrodes and thin porous film electrodes of highly reduced functionalized graphene to demonstrate that the introduction of electrode porosity gives rise to strong apparent electrocatalytic effects resulting in vastly improved electrode selectivity. This is despite graphene showing no intrinsic advantage ov...

We use colloidal gels of graphene oxide in awater-ethanol-ionic liquid solution to assemble graphene-ionic liquid laminated structures for use as electrodes in electrochemical double layer capacitors. Our process involves evaporation of water and ethanol yielding a graphene oxide/ionic liquid composite, followed by thermal reduction of the graphene...

Laser conversion of commercial polymers to laser-induced graphene (LIG) using inexpensive and accessible CO2 lasers has enabled the rapid prototyping of promising electronic and electrochemical devices. Frequently used to pattern interdigitated supercapacitors, few approaches have been developed to pattern batteries—in particular, full cells. Herei...

Customized architecture and chemistry play a pivotal role in conferring exceptional permeability and selectivity to polyamide (PA) membranes for desalination and ionic separation. Herein, a new interfacial polymerization (IP) template, the ultrathin graphene oxide nanoribbon (GONR) networks, is developed to meet the need for minimizing the funnel e...

To achieve a balance between performance and durability in electrochemical energy conversion systems, such as fuel cells (FC) and water electrolyzers (WE), proton exchange membranes (PEMs) must be optimized for minimal thickness and resistance while maximizing gas rejection and durability. 2D materials, with Angstrom‐scale pores, hold the potential...

Lithium‐ion batteries (LIBs) are crucial for achieving sustainable energy goals due to their high energy density and long cycle life. They dominate markets like consumer electronics, electric vehicles, and stationary energy storage systems. However, current LIBs use liquid electrolytes, which are toxic, flammable, and their liquid state does not re...

Carbonaceous and carbon‐coated electrodes are ubiquitous in electrochemical energy storage and conversion technologies due to their electrochemical stability, lightweight nature, and relatively low cost. However, traditional reliance on conductive additives and binders leads to impermanent electrical pathways. Here, a general approach is presented...

Cathodic electrochemical intercalation/exfoliation of transition metal dichalcogenides (TMDs) with bulky tetraalkylammonium‐based cations is gaining popularity as it avoids the semiconducting (2H) to metallic (1T) phase transformation in TMDs like molybdenum disulfide (MoS2) and, generally, produces sheets with a larger aspect ratio – important for...

Graphene oxide (GO)-based membranes hold significant promise for applications ranging from energy storage to protective coatings, to saline water and produced water treatment, owing to their chemical stability and unique barrier properties achieving a high selectivity for water permeation. However, unmodified GO membranes are not stable when submer...

Metal-insulator-metal (MIM) diodes based on black titanium dioxide are fabricated and characterized for the first time by in situ hydrogen doping via plasma assisted atomic layer deposition (PAALD). Hydrogen- doped...

The principal sources of new renewable energy, such as solar and wind power, depend strongly on the weather conditions, leading to the unstable electric power supply. Energy storage systems (ESS) has been developed to address this problem. One of the most promising technologies for energy storage device is redox flow batteries due to its high capac...

Li-ion batteries are the backbone of all electric vehicles (EVs) in production today [1]. However, they compete poorly against the few-minute refueling time of fossil fuel powered vehicles [2, 3]. To successfully replace fossil fuel powered vehicles, the EV batteries must support charging rates under the 15-minute mark as determined by the eXtreme...

Among the many recently developed photo-catalytic materials, graphitic carbon nitride (g-C3N4) shows great promise as a catalytic material for water split-ting, hydrogen generation, and related catalytic applications. Herein, synthesized bulk g-C3N4 is simply irradiated under a 35 fs pulse at mixed photon energies (800 nm and its second harmonic)....

Electrolyte mediated assembly of graphene based supercapacitor using adsorbed IL/non ionic surfactant.

Hypothesis: Coating approaches which trap nanoparticles at an interface have become popular for depositing single-layer films from nanoparticle dispersions. Past efforts concluded that concentration and aspect ratio dominate the impact on aggregation state of nanospheres and nanorods at an interface. Although few works have explored the clustering...

Correction for ‘Core–shell defective TiO 2 nanoparticles by femtosecond laser irradiation with enhanced photocatalytic performance’ by Bersu Bastug Azer et al. , Mater. Adv. , 2023, https://doi.org/10.1039/d3ma00019b.

The use of inexpensive and widely available CO2 lasers to selectively irradiate polymer films and form a graphene foam, termed laser-induced graphene (LIG), has incited significant research attention. The simple and rapid nature of the approach and the high conductivity and porosity of LIG have motivated its widespread application in electrochemica...

Engineering defects in titanium dioxide (TiO2) is becoming increasingly important to enhance its photocatalytic performance by increasing active sites and lowering its band gap from the UV region to the visible light region. Herein, we demonstrate a simple method to create stable surface defects by exposing TiO2 dispersions to femtosecond laser irr...

Mixed-phase (MP) metal disulfides have interesting electrochemical properties which originate from the generation of the abundance of electrochemically active sites and a higher structural stability as compared with crystalline materials. However, there is less exploration in the design and performance of the MP materials for supercapacitors applic...

Aqueous sodium-ion batteries are the promising candidates for large scale energy storage applications owing to their cost effectiveness and environmental safety. However, the development of a stable cathode material with high capacity is still a challenging task for the commercial viability of aqueous electrolyte-based sodium-ion batteries. This wo...

The Cover Feature illustrates the use of a biomass‐derived polymer for the direct laser writing fabrication of carbon‐based electrodes for a non‐enzymatic electrochemical sensor of ascorbic acid. More information can be found in the Research Article by L. Fernandes Loguercio et al.

Redox flow batteries (RFBs) are a promising technology for grid scale stationary energy storage to complement renewable energy systems. These batteries have a relatively low energy density; however, they offer important advantages, including: long life-time; decoupled energy (arbitrarily large electrolyte volume) and power (electrode area); high ro...

Silicon anodes are thought to soon replace graphite in next-generation Li-ion batteries due to silicon’s high capacity (3590 mAh/g for the Li 15 Si 4 alloy at room temperature), availability and natural abundance. However, lithiation of silicon causes a large volume expansion (~300%) which can cause pulverization of the primary silicon particles, c...

With decades of engineering, lithium-ion batteries are beginning to reach their fundamental energy density limits. As such, next generation chemistries that can store significantly more energy are essential for electrification of vehicles, improved portable electronics, and increased adoption of renewable energy sources. Lithium-sulfur batteries ha...

Current lithium-ion batteries consist of a graphite anode and a metal oxide cathode. Due to their relatively high energy density and rechargeability, they have enabled various applications over the past few decades. However, significant improvements to battery cost, performance, and safety for applications such as vehicle electrification require a...

Due to the considerable importance of preventing and treating diseases, efficient detection methods are required to monitor levels of ascorbic acid (AA) in beverages, foods, dietary supplements, and biological fluids. In this work, an efficient, easy handling, low cost, and simple fabrication process for non‐enzymatic electrochemical sensors was fa...

Advancements in electrochemical energy storage devices such as batteries and supercapacitors are vital for a sustainable energy future. Significant progress has been made in developing novel materials for these devices, but less attention has focused on developments in electrode and device manufacturing. While electrodes are traditionally made thro...

The increase in global population, industrialization and need for water security has fostered a demand for novel technologies related to water treatment and purification. The oxygen demand of a given water matrix can provide useful information on the presence of organic compounds within a sample and can inform decisions on water use and treatment....

Ionic liquids (ILs) are being increasingly used as processing aids to formulate electrode/electrolyte composites where the electrolyte acts as a template, defining the effective electrolyte-filled pore space between 2D materials such as graphene and MXenes. This is often facilitated with non-ionic surfactants. However, little is currently known abo...

Advanced energy storage systems require high energy and power densities, abundant availability of raw materials, low cost, reasonable safety, and environmental benignancy. Owing to their exceptionally high theoretical gravimetric energy density (2600 W h kg⁻¹) and specific capacity (1675 mA h g⁻¹), lithium sulfur batteries (LSBs) are considered a p...

Adhesion between similar and dissimilar materials is essential to many biological systems and synthetic materials, devices, and machines. Since the inception of adhesion science more than five decades ago, adhesion to a surface has long been recognized as beyond two-dimensional. Similarly, molecular conformation - the three-dimensional arrangement...

Oil and gas industries produce a huge amount of wastewater known as produced water which contains diverse contaminants including salts, dissolved organics, dispersed oils, and solids making separation and purification challenging. The chemical and thermal stability of graphene oxide (GO) membranes make them promising for use in membrane pervaporati...

Silicon anodes have a theoretical capacity of 3590 mAh g⁻¹ (for Li15Si4, at room temperature), which is tenfold higher than the graphite anodes used in current Li‐ion batteries. This, and silicon's natural abundance, makes it one of the most promising materials for next‐generation batteries. Encapsulating silicon nanoparticles (Si NPs) in a crumple...

Despite silicon being a promising candidate for next-generation lithium-ion battery anodes, self-pulverization and the formation of an unstable solid electrolyte interface, caused by the large volume expansion during lithiation/delithiation, have slowed its commercialization. In this work, we expand on a controllable approach to wrap silicon nanopa...

Laser‐scribed carbonization of polyimide (PI), also known as laser‐induced graphene (LIG), has been used to fabricate flexible and conductive traces on polymer films. With the assistance of electrical tests, scanning electron microscopy (SEM) and Raman spectrometry, a systematic procedure, was used to investigate the effect of laser operating param...

Binders play an important role in electrode processing for energy storage systems. While conventional binders often require hazardous and costly organic solvents, there has been increasing development toward greener and less expensive binders, with a focus on those that can be processed in aqueous conditions. Due to their functional groups, many of...

Hexagonal boron nitride (hBN) is being increasingly used in optoelectronic devices to electronically and/or chemically isolate materials like graphene and carbon nanotubes from the environment or other device components. Solution exfoliation is a scalable method to produce large quantities of nanometer-thick hBN but it remains challenging to integr...

Ultrasmall particle size (<10 nm) and rich oxygen vacancies are two sought‐after characteristics for titanium dioxide (TiO2) to achieve high performance, namely, high rate and high storage capacity, when being used as an anode in lithium‐ion batteries (LIBs). However, free TiO2 particles simultaneously possessing both characteristics have not been...

A rapid microwave hydrothermal process is adopted for the synthesis of titanium dioxide and reduced graphene oxide nanocomposites as high-performance anode materials for Li-ion batteries. With the assistance of hydrazine hydrate as a reducing agent, graphene oxide was reduced while TiO2 nanoparticles were grown in situ on the nanosheets to obtain t...

The high interest in wearable technologies has inspired an increased demand for portable, flexible energy storage devices. Currently, most commercial electrochemical energy storage units, such as supercapacitors, are available only in rigid formats, failing to meet the flexibility standards that allow their integration into wearables such as smart...

Methane, the primary component of natural gas, is a significant contributor to global warming and climate change. It is a harmful greenhouse gas with an impact 28 times greater than carbon dioxide over a 100-year period. Preventing methane leakage from transmission pipelines and other oil and gas production activities is a possible solution to redu...

Lithium-sulfur (Li-S) batteries are promising next-generation rechargeable energy storage systems due to their high energy density and use of abundant and inexpensive materials. However, rapid self-discharge and poor cycle stability due to the solubility of intermediate polysulfide conversion products have slowed their commercialization. Herein, we...

Molybdenum disulfide (MoS 2 ) is a 2D material of the transition metal dichalcogenide family which has recently gained significant attention for use in supercapacitors. MoS 2 can exist as several polymorphs such as the 2H and 1T which are semiconducting and semi-metallic, respectively. The 2H phase, found in nature, is the most stable form of MoS 2...

Supercapacitors based on 1T-molybdenum disulfide (MoS 2 ) have achieved record high volumetric capacitance due to a combination of high surface area, bulk density and the ability for ions to easily penetrate between restacked layers. While many promising MoS 2 -based devices have been demonstrated, few works have examined capacitive charging mechan...

Current lithium-ion batteries consist of a graphite anode and a metal oxide cathode. Due to their relatively high energy density and rechargeability, they have enabled various applications over the past few decades. However, significant improvements to battery cost, performance, and safety for applications such as vehicle electrification require a...

The metallic, 1T polymorph of molybdenum disulfide (MoS2) is promising for next-generation supercapacitors due to its high theoretical surface area and density which lead to high volumetric capacitance. Despite this, there are few fundamental works examining the double-layer charging mechanisms at the MoS2/electrolyte interface. This study examines...

“Smart” stimuli-responsive materials have been the subject of decades of research because of their versatility and particularly their use in medical and sensing applications. While these materials are often composed exclusively of responsive polymers, there is growing interest in smart hybrid systems that contain at least two distinct components, e...

Rapid prototyping methods such as additive manufacturing (three dimensional printing) and laser scribing have attracted much attention for manufacturing next-generation electrochemical energy storage devices because of their simplicity, low cost, medium throughput, and ability to prepare electrodes with unique form factors and multiple functionalit...

The production of exfoliated MoS2 via lithium intercalation has been widely used to prepare 1T polytype dominated MoS2 (1T-MoS2) monolayers. These metallic single-layers hold promise as high-performance electrodes for various electrochemical applications as well as for direct conversion to the semiconducting 2H polytype (2H-MoS2), a material of sig...

The use of low-cost and widely available infrared lasers to pattern laser-induced graphene (LIG) into commercial polymers has incited intense research over the past few years due to its simplicity and ability to create various electrical and electrochemical devices. While the highest performing devices have been created using costly synthetic polym...

Graphene is emerging as an excellent material choice for high-performance electrical and electrochemical devices such as humidity sensors. The rapid technological evolution in additive manufacturing (AM) enables freedom to design and process multiple materials for scalable fabrication of sensors. Herein, we introduce a hybrid AM approach to fabrica...

Methane is a potent greenhouse gas with large emissions occurring across gas distribution networks and mining/extraction infrastructure. The development of inexpensive, low-power electrochemical sensors could provide a cost-effective means to carry out distributed sensing to identify leaks for rapid mitigation. In this work, we demonstrate a simple...

The Langmuir-Blodgett technique is one of the most controlled methods to deposit monomolecular layers of floating or surface active materials but has lacked the ability to coat truly large area substrates. In this work, by manipulating single layer dispersions of graphene oxide (GO) and thermally exfoliated graphite oxide (TEGO) into water-immiscib...

Single layer graphene-based materials and molybdenum disulfide (MoS2) hold significant promise for next-generation supercapacitors because of their high theoretical surface area and their ability to be assembled into dense electrodes. While significant research has emerged in the last few years devoted to MoS2 and graphene-MoS2 hybrid electrode sys...

The lithium–sulfur battery is a promising next‐generation rechargeable battery system which promises to be less expensive and potentially fivefold more energy dense than current Li‐ion technologies. This can only be achieved by improving the sulfur utilization in thick, high areal loading cathodes while minimizing capacity fading to realize high pr...

Graphenic material/biopolymer nanocomposites have attracted attention for use in next generation flexible and degradable electronics. However, achieving high electrical conductivity (above 10 S/m) and favorable mechanical properties in such materials remains a challenge. In this work, reduced graphene oxide (rGO)/polyhydroxybutyrate (PHB) films wer...

Methane is the primary component of natural gas. As a result of mining and defects in the distribution network, methane emissions occur throughout the oil and gas industry. This corresponds to the largest anthropogenic source of the potent greenhouse gas and leads to a significant loss in revenue for the oil and gas industries: 60% of methane loss...

Improvements to miniaturized and flexible energy storage are required for a variety of current and next-generation applications ranging from wearable devices to smart credit cards. IR laser patterning of commercially available polymer substrates (ex. Kapton) has become a versatile platform for the rapid prototyping and final fabrication of electrod...

Supercapacitors, also known as electric double-layer capacitors (EDLCs), are able to store energy rapidly and reversibly through the formation of a double-layer of electronic and ionic charge, closely spaced, at the electrode/electrolyte interface. [1-2] Due to the combination of various advantageous properties, such as efficient operation at high...

The electrochemically available surface area and porosity of 2D materials is difficult to control due to the strong aggregation and restacking phenomena that occur when single layers are processed into thin or thick film electrodes. Furthermore, the distributed resistance, the potential for pore-size related effects and the uncertainty in relating...

The fabrication of long-lived, durable, superhydrophobic surfaces using a manufacturable process is an important challenge for material science. Significant advances have been reported; however, many surfaces suffer from fragility, nonmanufacturable fabrication techniques, and temporal instability. Such challenges have limited commercial scale appl...

Silver nanowire transparent electrodes have shown considerable potential to replace conventional transparent conductive materials. However, in this report we show that Joule heating is a unique and serious problem with these electrodes. When conducting current densities encountered in organic solar cells, the average surface temperature of indium t...

Graphene-based polymer nanocomposites have demonstrated significant promise to create commercially viable electromagnetic interference (EMI) shielding to protect the next-generation of electronic materials from radiative pollution. In the present study, we carry out a systematic analysis of the dynamic mechanical, dielectric, electrical and X-band...

By manipulating colloidal dispersions of chemically exfoliated molybdenum disulfide (MoS2) into an appropriate spreading solvent, we demonstrate, for the first time, the ability to form stable, floating MoS2 Langmuir films without the use of surfactants or significant material loss into the aqueous sub-phase. While the floating sheets can be compre...

Additive manufacturing (AM), also known as 3D printing, is emerging as a promising method for the fabrication of complex 3D structures and has the potential to replace the conventional techniques used in the manufacture of commercial devices based on advanced materials. Graphene has shown superior performance in various electronic devices such as e...

The addition of dehydrated sucrose nanoparticles increases the gravimetric capacitance of electrochemical double-layer capacitor electrodes produced via the evaporative consolidation of graphene oxide-water-ionic liquid gels by more than two fold. Dehydrated sucrose adsorbs onto graphene oxide and serves as a spacer, preventing the graphene oxide f...

A mathematical model for the dip coating process has been developed for cylindrical geometries with non-Newtonian fluids. This investigation explores the effects of the substrate radius and hydrodynamic behavior of the non-Newtonian viscous fluid on the resulting thin film on the substrate. The coating fluid studied, Dymax 1186-MT, is a resin for f...

While graphene and other carbonaceous nanomaterials have shown promise in a variety of electrochemical applications, measurement of their intrinsic performance is often confounded with effects related to the complexities due to diffusion in a porous medium. To by-pass this limitation, we use effectively non-porous tiled monolayers of reduced graphe...

We demonstrate that functionalized graphene, rich with lattice defects but lean with oxygen sites, catalyzes the reduction of Co(bpy)3(III) as well as platinum does, exhibiting a rate of heterogeneous electron transfer, k0, of ~ 6 × 10(-3) cm/s. We show this rate to be an order of magnitude higher than on oxygen site-rich graphene oxide, and over t...

We have covalently grafted tetrazine derivatives to graphene oxide through nucleophilic substitution. Since the tetrazine unit is electroactive and nitrogen-rich, with a reduction potential sensitive to the type of substituent and degree of substitution, we used electrochemistry and X­ray photoelectron spectroscopy to demonstrate clear evidence for...

The intrinsic electrocatalytic properties of functionalized graphene sheets (FGSs) in nitric oxide (NO) sensing are determined by cyclic voltammetry with FGS monolayer electrodes. The degrees of reduction and defectiveness of the FGSs are varied by employing different heat treatments during their fabrication. FGSs with intermediate degrees of reduc...

Electrodes used in electroanalysis which are based on carbonaceous nanomaterials such as carbon nanotubes or graphene often exhibit large degrees of porosity. By systematically varying the morphology of functionalized graphene electrodes from nearly flat to highly porous, we demonstrate experimentally that minute amounts of electrode porosity have...

Method of making a graphene-ionic liquid composite. The composite can be used to make electrodes for energy storage devices, such as batteries and supercapacitors. Disclosed and claimed herein is method of making a graphene-ionic liquid composite, comprising combining a graphene source with at least one ionic liquid and heating the combination at a...

We present a general method for characterizing the intrinsic electrochemical properties of graphene sheets, such as the specific double-layer capacitance, in the absence of porosity-related artifacts and uncertainties. By assembling densely tiled monolayers of electrically insulating or conductive functionalized graphene sheets onto electrode subst...

Graphene-based electrodes have recently gained popularity due to their superior electrochemical properties. However, the exact mechanisms of electrochemical activity are not yet understood. Here, we present data from NADH oxidation and ferri/ferrocyanide redox probe experiments to demonstrate that both (i) the porosity of the graphene electrodes, a...

Surfactant or polymer directed self-assembly has been widely investigated to prepare nanostructured metal oxides, semiconductors, and polymers, but this approach is mostly limited to two-phase materials, organic/inorganic hybrids, and nanoparticle or polymer-based nanocomposites. Self-assembled nanostructures from more complex, multiscale, and mult...

To homogenize light emitted from fiber optic diffusers for photodynamic therapy (PDT), novel coating materials with tunable properties were designed. A class VI medical grade UV-curable acrylic resin for biomedical applications was used for the polymer matrix, and titanium dioxide (TiO2) was added to the resin as a scattering agent. UV-curability o...