A discovery from the materials laboratory at Universitas Indonesia has opened a new perspective on affordable and environmentally friendly solar cells. Dr. drg. Bambang Priyono, S.U., together with his research team from the Department of Metallurgical and Materials Engineering, Universitas Indonesia, successfully demonstrated that titanium dioxide (TiO₂) nanoparticles synthesised through a sol-gel process and treated with hydrothermal methods could function as an active component in dye-sensitized solar cells (DSSCs)—a type of solar cell that uses dye molecules as light absorbers. Published in the 2018 edition of IOP Conference Series: Materials Science and Engineering, this research addressed a fundamental question: at what hydrothermal treatment temperature can the best performance be achieved?
Why Lithium Batteries Need Improvement
Lithium-ion batteries have long served as the backbone of everyday electronic devices, ranging from smartphones to electric vehicles. However, conventional anode materials currently used still have limitations, particularly in terms of charging speed and energy storage capacity under high-current conditions.
One promising candidate for anode material is Li₄Ti₅O₁₂, commonly known as LTO. This material is recognized for its chemical stability and safety; however, its natural electrical conductivity is relatively low. This is where ZnO plays an important role. By incorporating ZnO nanorods into LTO, researchers aimed to improve electrical conductivity while increasing the active surface area of the material, allowing lithium ions to move more freely and rapidly.
The research team synthesized LTO using the solid-state sol-gel method, a chemical process that transforms a solution into a solid material through a series of gradual reactions. ZnO nanorods were then synthesized separately and incorporated into LTO at three different compositions: 4, 7, and 10 wt%.
More Is Not Always Better
The test results revealed a pattern that was not entirely intuitive. Many people might assume that adding more ZnO would continuously improve battery performance. However, the findings showed otherwise.
At a composition of 4 wt% ZnO, the LTO/ZnO material demonstrated the highest surface area of 75.545 m²/g, the lowest charge-transfer resistance of 87.70 ohms, and the best specific capacity. In contrast, when ZnO content was increased to 7 and 10 wt%, the surface area decreased and electrical resistance increased. Observations using Scanning Electron Microscopy (SEM) revealed the reason: ZnO particles began to aggregate and form agglomerates that blocked the pores of LTO, restricting ion movement.
“Increasing ZnO content affects the conductivity of the samples, with the highest conductivity observed in LTO/ZnO 4%, while the lowest conductivity was found in LTO/ZnO 10%.”
During charge-discharge testing at a high current rate of up to 20C, LTO/ZnO with 4 wt% ZnO was still able to maintain a discharge capacity of 24.87 mAh/g. Meanwhile, LTO/ZnO with 7 wt% ZnO dropped significantly to only 8.4 mAh/g under the same conditions. This indicates that batteries containing 4 wt% ZnO are considerably more resilient under fast-charging conditions, making them highly relevant for applications such as electric vehicles and large-scale energy storage systems.
From Laboratory Research to Sustainable Energy
Although the achieved capacity of 110.2 mAh/g has not yet reached the theoretical capacity of pure LTO, which is 175 mAh/g, this research demonstrates that ZnO nanorod incorporation can significantly improve the charge-discharge capability of LTO, allowing operation at rates up to 20C. Previously, experiments without ZnO addition could only achieve a maximum rate of 10C.
This achievement is highly relevant to the increasing global demand for reliable energy storage systems. Renewable energy sources such as solar and wind power are intermittent; therefore, efficient batteries capable of storing and releasing energy rapidly are essential. Research such as this represents one of the building blocks supporting the global transition toward sustainable energy.
For the field of dentistry, research of this nature may appear distant from everyday clinical practice. However, the presence of researchers such as Dr. drg. Bambang Priyono, S.U., who crosses disciplinary boundaries, strengthens the contribution of health science academics to international materials science research. It serves as a reminder that innovation does not always emerge from the places where it is most expected.
Authors: Achmad Zam Zam Aghasy, DDS, M.Kes.; Hazra Alifia Muharam
Photo: Pexels
Source DOI: https://doi.org/10.1088/1757-899X/541/1/012030