DGIST enhances quantum dot solar cell performance

by Riko Seibo

Tokyo, Japan (SPX) Oct 04, 2024

A research team led by Professor Jongmin Choi from the Department of Energy Science and Engineering at DGIST, in collaboration with Gyeongsang National University’s Professor Tae Kyung Lee and Kookmin University’s Professor Younghoon Kim, has developed a new method that significantly boosts the performance and longevity of perovskite quantum dot solar cells. Their innovative approach addresses a key issue: surface distortions on quantum dots that hinder solar cell efficiency.

Perovskite quantum dots are widely regarded as essential for next-generation solar cells due to their high light-to-electricity conversion efficiency and scalability. However, the process of replacing the “ligands” on their surface often causes distortions, akin to crumpled paper, that degrade solar cell performance.

The research team tackled this problem by introducing short ligands that firmly grip both sides of the quantum dots. This method effectively restores the quantum dot’s distorted surface, resembling the process of flattening crumpled paper. By smoothing the surface, they significantly reduced defects and improved both the performance and the stability of the solar cells. The power conversion efficiency rose from 13.6% to 15.3%, and the cells maintained 83% of their performance over 15 days, marking a major advancement in solar cell technology.

“Through this research, we could minimize surface defects on the quantum dots and stabilize their surfaces by newly adopting these amphiphilic ligands, thereby significantly improving the efficiency and stability of the solar cells,” explained Professor Jongmin Choi. He also noted the team’s intention to extend this approach to other photoelectric devices in the future.

This study, a collaborative effort by DGIST, Gyeongsang National University, and Kookmin University, was supported by the National Research Council of Science and Technology, the DGIST R and D Program, and the New Faculty Research Foundation at Gyeongsang National University. The findings were published in the ‘Chemical Engineering Journal’ on September 15, 2024.

Research Report:Multifaceted anchoring ligands for uniform orientation and enhanced cubic-phase stability of perovskite quantum dots

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Fire breaks out at Chinese battery giant CATL plant

by AFP Staff Writers

Beijing (AFP) Sept 29, 2024

A fire broke out Sunday at a factory belonging to Chinese battery giant CATL, which supplies electric vehicle makers including Tesla, but only a “relatively small” impact on operations is expected, the company said.

A CATL spokesperson said no injuries or casualties had occurred at the plant in the coastal city of Ningde, and that “the reasons behind this accident are still under investigation”.

Emergency services were sent to the plant to fight the fire and to organise the evacuation of any people who were inside the 15,000 square metre (160,000 square feet) site, a statement by the Dongqiao Economic and Technological Development Zone said.

Firefighters were alerted to the blaze just before 11:30 AM local time (0330 GMT).

It was not immediately clear what was produced at the plant, CATL’s base in the eastern province of Fujian, but the company said the effect of the now extinguished fire would not be significant.

“The impact to CATL’s overall production operation is relatively small,” the spokesperson said.

Videos published by the Chinese business media outlet Cailianshe, and posted on the Weibo social network, showed parts of a large white building in flames with thick gray smoke rising into the air.

AFP could not immediately verify the authenticity of the images.

CATL was founded in 2011 and produces more than a third of the electric vehicle batteries sold worldwide for automakers that include Mercedes-Benz, BMW, Volkswagen, Toyota, Honda and Hyundai.

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A high-energy-density Mars battery designed for long-term missions

by Clarence Oxford

Los Angeles CA (SPX) Sep 30, 2024

The extreme environmental conditions on Mars, with its 95.32% carbon dioxide atmosphere and significant temperature fluctuations, pose major challenges for energy storage systems on the planet. To overcome these hurdles, Prof. Peng Tan and Dr. Xu Xiao from the University of Science and Technology of China have developed a new type of Mars battery, which uses the Martian atmosphere as a fuel source during discharge.

This innovative battery system minimizes weight, making it ideal for space missions. Once discharged, the battery can be recharged using solar energy collected from the Martian surface, enabling repeated use. The researchers also simulated Martian surface conditions, including wide temperature ranges, to create a system capable of consistent power output.

The Mars battery operates efficiently even at low temperatures, such as 0 C, where it achieves an energy density of up to 373.9 Wh kg-1 and offers a charge/discharge cycle life of 1,375 hours, providing approximately two months of continuous operation on Mars. Its functionality hinges on the formation and breakdown of lithium carbonate, with trace gases like oxygen and carbon monoxide in the Martian atmosphere acting as catalysts to enhance carbon dioxide conversion.

The team enhanced the reaction efficiency by designing integrated electrodes and a folded cell structure, maximizing the reaction area with the Martian atmosphere. Increasing the cell size to 4 cm, they further improved the battery’s energy density to 765 Wh kg-1 and 630 Wh l-1 in a pouch format.

According to the researchers, this development represents an essential proof-of-concept for the application of Mars batteries in the planet’s environment. They plan to continue researching solid-state Mars batteries, addressing challenges such as electrolyte volatility under low pressure, and improving thermal and pressure management systems. Their work lays the groundwork for multi-energy complementary systems, essential for future space exploration missions.

Research Report:A high-energy-density and long-cycling-lifespan Mars battery

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