As more and more people from all walks of life turn to their mobile phones to perform lifestyle functions – listening to music, watching movies, ordering food, navigating new places, among others – and as the public moves toward electric vehicles (EVs) for transportation, finding efficient materials to store and manage energy is a challenge.
Imagine smartphones capable of recharging in minutes and days or electric cars capable of traveling longer distances on a single charge.
A recent study by researchers – Hodam Karnajit Singh, Prajna P Mohapatra, Subingya Pandey and Pamu Dobbidi – from IIT Guwahati has brought us closer to this reality by exploring the potential of a particular type of ceramic composite material. These are advanced materials designed to have extraordinary electrical properties.
But it’s not just about storing more energy. These materials also exhibit fascinating dielectric relaxation behaviors: they can essentially respond to changes in electric fields in a way that can be extremely useful for electronic applications such as sensors or even in the development of stealth technologies, by absorbing the signals unwanted microwaves.
How it’s made
At the heart of this research is the creation of a dense ceramic composite from a mixture of two specific types of ferrites: M-type hexaferrite and an inverse spinel ferrite (NCZFO). When combined into the new composite material, it exhibits what scientists call “colossal permittivity.” Permittivity is a measure of a material’s ability to store an electric charge. Higher permittivity means more electricity can be stored, which is exactly what we need for better batteries and more efficient electronic devices.
However, creating these composites is not simple; this involves carefully mixing and heating materials in a solid-state process – a method notable for its precision and control of material properties.
The researchers began by precisely weighing the pure powders of barium carbonate (BaCO3), strontium carbonate (SrCO3) and iron oxide (Fe2O3) needed for the hexaferrite phase.
The powders were then ball milled for 12 hours. After grinding, the resulting slurry was dried in a slow heating process and then calcined (the process in which materials are heated to a high temperature in the absence or limited supply of air or oxygen). This step is crucial to initiate chemical reactions between the raw materials to form the hexaferrite phase.
The other ferrite – reverse spinel ferrite (NCZFO) – was also prepared using a solid-state reaction method. The proportions of nickel, cobalt, zinc and iron precursors were carefully controlled, similar to the hexaferrite preparation.
The synthesized M-type hexaferrite and NCZFO were then combined in varying percentages (80 to 20 percent, 60 to 40 percent, and 40 to 60 percent of hexaferrite to NCZFO, respectively) to explore the effects of different concentrations on the composite. properties.
The mixed powders were ball milled for an additional 15 hours to ensure uniform distribution of both phases. The homogenized powder mixture was then pressed into circular plates using a hydraulic press. These plates were sintered at 1250°C for 3 hours. Sintering further densifies the material, which improves chemical bonds between components and optimizes microstructural properties crucial to achieving colossal permittivity.
The researchers varied the concentrations of each component to see how it affected the material’s properties. They found that adjusting these concentrations changed the microstructure of the material, including the size of grains within the composite and the presence of tiny defects. These microscopic changes have a dramatic impact on how electricity is stored and flows through the material.
High permittivity materials can revolutionize energy storage solutions, making devices such as capacitors much more efficient. Batteries that charge in a fraction of the current time, electric vehicles that require less frequent charging, or even new types of sensors that can more accurately detect changes in the environment are becoming a possibility.
These materials could also lead to advances in telecommunications, enabling devices capable of operating at higher frequencies, crucial for the next generation of wireless communications. In a world increasingly concerned about electromagnetic interference, these composites offer a promising solution. They could be used to protect sensitive equipment, from medical devices to military hardware, protecting them from interference and ensuring they operate reliably.
For a sustainable future
For ordinary people, this research may seem far removed from daily concerns. Yet its implications are profound: In the not-so-distant future, it could mean more durable, more reliable and more powerful electronics.
It’s not just about convenience; it’s a question of sustainability. Devices that charge faster and hold their charge longer are devices that use less power over their lifespan.
As we move towards a more electrified world, efficient energy storage becomes crucial. These ceramic composites could play a vital role in this transition, helping to store energy more efficiently, whether it is harvested from the sun, wind or waves.
SHARE
Published on April 14, 2024
