Innovations in Aqueous Electrochemical Energy Storage Devices
Researchers at UNH are developing new solutions for rechargeable energy storage devices that are safer, more environmentally friendly and more affordable than the options that are currently on the market.
As world energy consumption continues to increase, the installation of renewable energy harvesting and generation devices, such as solar panels and wind turbines, has been growing worldwide. Renewable energy sources, especially those from sun and wind, do not typically meet on-peak and off-peak load demands. As a result, there is a strong need for rechargeable energy storage devices (e.g. batteries) so that electricity generated during off-peak hours can be stored efficiently and economically for later use during peak demand. Cost-effective and safe energy storage has long been described as the key for the widespread adoption of renewable energy practices.
Xiaowei Teng, professor and chair of chemical engineering at UNH, is leading the charge to research alternative methods for building energy storage devices that can compete with existing solutions like lithium-ion batteries, which can be found in everything from cell phones to Tesla cars. Lithium-ion batteries offer excellent performance but have safety limitations due to their use of toxic materials and flammable organic electrolytes. Lithium is also a limited and expensive resource.
Teng’s research focuses on aqueous electrochemical energy storage devices that use a water-based electrolyte, which is less likely to combust if exposed to air or moisture. Rechargeable aqueous batteries, especially ones using earth-abundant and less toxic materials, have shown great promise, particularly for renewable energy storage because of their high safety, low cost and environmental friendliness. While aqueous batteries have many advantages, the use of a water-based electrolyte provides some challenges in achieving adequate energy capacity retention and power performance (time required to charge and discharge the devices) as well as scalability in production. Teng and his teams have developed several novel methods for the preparation of electrode materials that will help overcome these challenges.
Manganese Oxide Compositions and their Use as Electrodes for Aqueous Phase Energy Storage Devices
This innovation is a composition and method of preparing manganese oxide materials for use as an electrode in an energy storage device. These manganese oxide electrode materials can support inexpensive, large-scale manufacturing and are ideal for stationary applications. The nanoparticle size enables these electrode compositions to reach an energy storage potential of up to 2.7V (comparable to most standard non-aqueous devices) and a lifespan of greater than 10,000 charge/discharge cycles (much longer than existing non-aqueous devices). As an aqueous phase energy storage device, electrode drying is unnecessary, resulting in lower cost of production and cell packaging when compared to non-aqueous devices.
Preparation Of: I.) Intercalative Metal Oxide/Conductive Polymer Composites as Electrode Materials for Rechargeable Batteries; II.) Sodium Rich Manganese Oxide Hydrate with Capacity for Aqueous Na-ion Electrochemical Energy Storage
I.) This innovation is a new approach for preparing intercalative metal oxide/conductive polymer composites as electrode materials for rechargeable batteries. This innovation presents a scalable energy-efficient synthetic routine that can be carried out at room temperature in benign conditions without heat or radiation. The intercalative structure (layering of the oxide and conductive polymer) is achieved by agitation (e.g. stirring) of the metal oxide and the conductive polymer in aqueous media for an extended period of time, such as 100-200 hours.
II.) Manganese oxide is the most promising electrode material. Manganese is the 10th most abundant element in the Earth’s crust and second most common metal after iron. Among various manganese oxides, birnessite has a layered structure containing two-dimensional sheets of edge˗shared MnO6 octahedra. Birnessite is a low-cost and environmentally friendly layered material for aqueous electrochemical energy storage; however, its storage capacity is poor due to its narrow potential window in aqueous electrolyte and low redox activity. This innovation is a sodium rich disordered birnessite for aqueous sodium-ion electrochemical storage with a much-enhanced capacity and cycling life.
Lead Innovator, Xiaowei Teng, Ph.D.
The unifying theme of Professor Teng's research team is the fundamental investigation of chemical and physical properties of functional nanomaterials, using X-ray, electron, neutron and electrochemical tools, for applications in the fields of energy technologies, catalysis and materials science. The current projects in Prof. Teng's research team include aqueous electrochemical energy storage, direct ethanol fuel cell reaction and aqueous-phase heterogeneous catalysis.