Research Overview
Our research spans a broad range of interdisciplinary electrochemistry topics, including synthetic inorganic chemistry, electrocatalysis, renewable energy, materials science, and engineering. Reflecting this diversity, our research students come from various Schools and Departments, such as Chemistry, Physics, Biomedical, and Chemical Engineering. We employ a variety of synthesis strategies, including microwave-assisted methods, laminar flow co-precipitation, hydrothermal processes, and electrospinning, to develop novel materials for sustainable energy, environmental, and health applications.
Current research activities within the Ozoemena group focus on three main areas:
- Energy Storage: This includes the development of modern batteries, supercapacitors, and supercapatteries.
- Energy Conversion: Specifically, fuel cell and electrolyzers.
- Electrochemical Sensors: Including chemical and immunosensors, as well as gas sensors, with a particular focus on poverty-related diseases such as tuberculosis, cholera, human papilloma virus (cervical cancer), and drugs of abuse.
Central to our work is a commitment to sustainable materials for a fossil-free energy future, with a focus on renewable resources, inorganic and carbon-based materials, and environmentally friendly processing. A key emphasis is on low-cost batteries using abundant mineral precursors, advancing practical and sustainable energy solutions.
Our research is supported by state-of-the-art facilities available in our laboratories and networks (please see Ozoemena MEET Group Facility page).
Research Areas
Electrochemical capacitors (‘Supercapacitors’)
Lithium-ion batteries
Conventional rechargeable lithium-ion batteries have long dominated, and are expected to continue leading, the consumer electronics and electric vehicle markets. To enhance safety and reduce costs, our research focuses on manganese-based (Mn-based) cathode materials. We develop high-energy spinel structures, lithium manganese nickel oxide (LMNO), and high-capacity layered oxides, including lithium nickel manganese cobalt oxides (NMC) and cobalt-free layered materials. Key challenges limiting the performance and broader adoption of these Mn-based electrodes include poor initial Coulombic efficiency and capacity fading during repeated charge/discharge cycles. To address these issues, we employ a range of microwave-assisted synthesis strategies to tune redox chemistry and stabilize material structures.
Sodium-ion & related mobile ion batteries
Sodium (Na) is considered the most promising alternative to lithium due to its low cost, abundance (it is the fourth most abundant element in the Earth’s crust), and global availability. Our research explores sodium-ion batteries (SIBs) as a compelling substitute for lithium-ion batteries, particularly for stationary or home energy storage where weight is less critical. Within the Ozoemena MEET group, we also investigate Mn-based rechargeable aqueous mobile-ion batteries (RAMIBs) and are exploring other ion carriers, including K⁺, Al³⁺, Zn²⁺, Mg²⁺, as well as dual-ion systems.
Lithium-sulfur batteries
Rechargeable lithium–sulfur batteries (LiSBs) are a highly promising next-generation technology, offering low cost, non-toxic sulfur, and a very high theoretical energy density of 2500 Wh/kg. Their practical application, however, is limited by poor sulfur utilization and polysulfide shuttling. Our research addresses these challenges through strategies such as confining sulfur and employing high-performance electrocatalysts and electrolytes to enhance efficiency and stability
Rechargeable Zinc-Air Batteries
Rechargeable zinc–air batteries (RZABs) are promising next-generation energy storage devices for home, stationary, and portable applications, offering low cost and a high theoretical specific capacity of 1086 Wh/kg by utilizing atmospheric oxygen. Their commercialization is limited by short cycle life and the lack of effective bifunctional electrocatalysts for the oxygen reduction (ORR) and evolution (OER) reactions. Our research explores advanced electrode materials and strategies, including magnetic enhancement, to overcome these challenges.
Fuel Cell Technologies
Fuel cells are electrochemical devices that convert fuels directly into electricity, with anodic reactions (hydrogen or alcohol oxidation) facilitated by precious metal catalysts and cathodic oxygen reduction reactions catalyzed by precious or non-precious materials. Our research addresses key challenges, such as reducing precious metal loading and enhancing electrode kinetics, by developing Pd- and Pt-based bimetallic and ternary anode catalysts along with advanced electrode support materials.
Four Zn–air batteries connected in series to split water and generate green hydrogen
Electrolyzers: Electrochemical Water-Splitting
Electrocatalytic water splitting powered by renewable electricity offers a promising route to green hydrogen for energy security and emission reduction. Efficient overall water splitting requires low-cost bifunctional electrocatalysts that enhance both hydrogen and oxygen evolution reactions, and our research focuses on developing such catalysts using carbon- and base-metal materials.
Set-up of a screen-printed carbon electrode (SPCE) modified with HPV-16 L1 antibody immunosensor, (C) typical square wave voltammetric responses toward antigenic HPV-16 L1 protein. Peteni et al. ACS Sens. 2023, 8, 2761−2770
Electrochemical Sensors
Our group develops electrochemical sensors, including immuno- and gas sensors, for applications such as poverty-related diseases (i.e., tuberculosis, HPV, cholera) and alcohol or drug detection. Leveraging materials from our energy research, we aim to meet the WHO’s ASSURED criteria: Affordable, Sensitive, Specific, User-friendly, Rapid and robust, Equipment-free, and Deliverable to those in need.
Solid-State Electrolytes
Solid-state electrolytes offer a safer and more robust alternative to liquid electrolytes and enable high-voltage, high-capacity energy storage. We are exploring several materials for all-solid-state, flexible, and wearable energy storage and sensor devices, including nanocomposite polymer electrolytes such as electrospun nanofibers reinforced with ceramic materials, and a recent work on the great potential of Li0.95Na0.05FePO4 (LNFP) as an ideal SSE due to its enhanced ionic conductivity and reliable stability in contact with lithium metal anode.
