Solar Energy

Compound commonly found in candles lights the way to grid-scale energy storage

Published

4 years ago

June 5, 2021

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Compound commonly found in candles lights the way to grid-scale energy storage

A compound used widely in candles offers promise for a much more modern energy challenge – storing massive amounts of energy to be fed into the electric grid as the need arises.

Scientists at the U.S. Department of Energy’s Pacific Northwest National Laboratory have shown that low-cost organic compounds hold promise for storing grid energy. Common fluorenone, a bright yellow powder, was at first a reluctant participant, but with enough chemical persuasion has proven to be a potent partner for energy storage in flow battery systems, large systems that store energy for the grid.

Development of such storage is critical. When the grid goes offline due to severe weather, for instance, the large batteries under development would kick in, boosting grid resilience and minimizing disruption. The batteries can also be used to store renewable energy from wind and solar, for use when the winds are quiet or the sun’s not shining.

Details of the research, supported by DOE’s Office of Electricity, are published in the May 21 issue of the journal Science.

“Flow battery technology is a critical part of the Department of Energy’s goal to reduce the cost of grid energy storage over the next decade,” said Imre Gyuk, director of Energy Storage at DOE’s Office of Electricity. “Progress has been rapid, and the cost has come down significantly, but further research is needed to make grid-scale energy storage widely available.”

Flow batteries for the grid: going organic

Scientists are making tremendous strides toward creating better batteries – storing more energy at lower cost and lasting longer than ever before. The results touch many aspects of our lives, translating to a more resilient electric grid, longer-lasting laptop batteries, more electric vehicles, and greater use of renewable energy from blowing wind, shining sun, or flowing water.

For grid-scale batteries, identifying the right materials and combining them to create a new recipe for energy storage is a critical step in the world’s ability to harness and store renewable energy. The most widely used grid-scale batteries use lithium-ion technology, but those are difficult to customize moment to moment in ways most useful to the grid, and there are safety concerns. Redox flow batteries are a growing alternative; however, most use vanadium, which is expensive, not easily available, and prone to price fluctuations. Those traits pose barriers to widespread grid-scale energy storage.

Alternative materials for flow batteries include organic molecules, which are far more available, more environmentally friendly and less expensive than vanadium. But organics haven’t held up well to the demands of flow-battery technology, usually petering out faster than required. Long-term stability of the molecules is important so they maintain their ability to perform chemical reactions for many years.

“These organic materials are made out of the most common materials available – carbon, hydrogen and oxygen,” said Wei Wang, the PNNL scientist who leads the flow battery team. “They are easily available; they don’t need to be mined, as substances like vanadium do. This makes them very attractive for grid-scale energy storage.”

In the Science paper, Wang’s team demonstrated that low-cost organic fluorenone is, surprisingly, not only a viable candidate but also a standout performer when it comes to energy storage.

In laboratory testing that mimicked real-world conditions, the PNNL battery operated continuously for 120 days, ending only when other equipment unrelated to the battery itself wore out. The battery went through 1,111 full cycles of charging and discharging – the equivalent of several years of operation under normal circumstances – and lost less than 3 percent of its energy capacity. Other organic-based flow batteries have operated for a much shorter period.

The flow battery the team created is only about 10 square centimeters, about the size of a large postage stamp, and puts out about 500 milliwatts of power, not even enough to power a cell phone camera. But the tiny structure embodies tremendous promise: Its energy density is more than twice that of the vanadium batteries in use today and its chemical components are inexpensive, long lasting and widely available.

Molecular engineering puts fluorenone into reverse

The development was made possible thanks to a team of scientists, including first author Ruozhu Feng, technical lead Xin Zhang and others.

PNNL scientists played an important role in developing the vanadium-based flow batteries used today. A few years ago the team turned its attention to organic molecules because of their broad availability and low cost. In 2018 Zhang joined the team as part of an effort to tune the material for energy storage, bringing deep knowledge of fluorenone from previous research in LEDs.

Fluorenone is also used in solar panels, in pharmaceuticals such as drugs to treat malaria, and in candles, to give them a pleasant scent. It’s inexpensive and readily available as a waste product from coal tar and from the manufacture of benzoic acid, a common food additive.

Zhang focused his attention on fluorenone as the heart of an aqueous (water-based) flow battery, but there were barriers. For one, the molecule wasn’t water-soluble enough. And the molecule hadn’t displayed redox reversibility in aqueous solutions; that is, scientists hadn’t demonstrated that it could both easily accept and donate electrons, two complementary and mandatory steps for a flow battery.

Feng created a series of complex chemical steps – what Wang calls “molecular engineering” – to transform fluorenone to a redox reversible, water-soluble compound. One part of the process has long been easy for fluorenone: to gain an electron in a process known as reduction. But it took dogged chemical persuasion by Feng to bring about the other half of the process – oxidation, the loss of an electron – to make the process reversible and suitable for energy storage.

Unexpectedly, Feng discovered that the ability of fluorenone to carry out reversible reactions is dependent on its concentration – more of the substance dissolved in the water makes the reversibility possible. Scientists hadn’t witnessed the phenomenon with organic molecules before.

“This is a great demonstration of using molecular engineering to change a material from one widely considered impossible for use into something useful for energy storage,” said Wang. “This opens up important new chemical space that we can explore.”

The team also increased the solubility of fluorenone in water, from almost 0 with pristine fluorenone up to 1.5 moles per liter, depending on the modifications to the compound. Solubility in a water-based flow battery is vital; the more the material dissolves in water, the more it’s available as a chemical partner in the swapping of electrons at the heart of the battery.

PNNL is encouraging commercialization of fluorenone-based aqueous redox flow batteries and, as a first step, has filed for a patent on the innovation.

The work on flow batteries is part of a large program at PNNL to develop and test new technologies for grid-scale energy storage. PNNL was chosen earlier this year as the home of the Grid Storage Launchpad, a facility created by DOE’s Office of Electricity to accelerate development and testing of large grid batteries. A chief goal is to increase the use of readily available materials and bring down the cost, making storage of renewable energy possible for longer periods.

In addition to Feng, Zhang and Wang, authors include PNNL scientists Vijayakumar Murugesan, Aaron Hollas, Ying Chen, Yuyan Shao, Eric Walter, Nadeesha Wellala, Litao Yan and Kevin Rosso. Several measurements using mass spectrometry and nuclear magnetic resonance were done at EMSL, the Environmental Molecular Sciences Laboratory, a DOE Office of Science user facility.

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Solar Energy

China says wind and solar energy capacity exceeds thermal for first time

Published

16 hours ago

April 27, 2025

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China says wind and solar energy capacity exceeds thermal for first time

By Sam Davies and Luna Lin

Beijing (AFP) April 25, 2025

China’s wind and solar energy capacity has surpassed that of mostly coal-powered thermal for the first time, the national energy body said Friday.

China, the world’s largest emitter of greenhouse gases that drive climate change, has pledged to peak carbon emissions by 2030 and achieve carbon neutrality by 2060.

While around 60 percent of China’s energy comes from coal, the country is also a renewable energy powerhouse, building almost twice as much wind and solar capacity as every other country combined, according to research published last year.

“In the first quarter of 2025, China’s newly installed wind and photovoltaic power capacity totalled 74.33 million kilowatts, bringing the cumulative installed capacity to 1.482 billion kilowatts,” the national energy body said.

That surpassed the installed capacity of thermal power (1.451 billion kilowatts) for the first time.

President Xi Jinping said on Wednesday that “no matter how the international situation changes”, the country’s efforts to combat climate change “will not slow down”.

Xi also said China would announce its 2035 greenhouse gas reduction commitments, known as Nationally Determined Contributions (NDCs), before COP30 in November and that it would cover all greenhouse gases, not just carbon dioxide.

President Donald Trump meanwhile has pulled the United States, the world’s second-largest polluter, out of the Paris climate accord while pledging a vast expansion in fossil fuel exploitation.

-‘Structural change’-

China’s new milestone comes as the country experiences explosive growth in renewable energy.

Last year, China added a record 357 gigawatts of wind and solar, 10 times the US’s additions.

It met a 2030 target to install 1,200 GW of solar and wind capacity almost six years early.

Friday’s announcement said that wind and solar additions in the first quarter had “far exceeded” China’s total increase in electricity consumption.

“This trend is very likely to continue in the following months and quarters in 2025,” Yao Zhe, Global Policy adviser at Greenpeace East Asia, told AFP.

That suggests China’s power sector is undergoing “structural change and the sector’s carbon emissions are one small step away from peaking”.

However, coal continues to play a key role in China’s energy mix.

“The intermittency of variable renewables like wind and solar… means it’s generally inappropriate to compare them to firm, dispatchable power sources like coal,” according to David Fishman, senior manager at the Lantau Group.

“There is indeed some combination of wind plus solar plus storage that equals one coal plant, but the determination is different everywhere in the world.”

And China’s energy consumption continues to grow — by 4.3 percent last year.

Covering that growth with renewable power is a “tough proposition for a developing country with a huge heavy industrial segment and a residential population that frankly doesn’t even use that much electricity on a per capita basis”, Fishman said.

Despite the renewable energy boom, China also began construction on 94.5 gigawatts of coal power projects in 2024, 93 percent of the global total, according to a February report from the Finland-based Centre for Research on Energy and Clean Air (CREA) and Global Energy Monitor (GEM) in the United States.

China’s coal production has risen steadily in recent years, from 3.9 billion tons in 2020 to 4.8 billion tons in 2024.

That is despite Xi pledging to “strictly control” coal power before “phasing it down” between 2026 and 2030.

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Solar Energy

A single molecule elevates solar module output and stability

Published

4 days ago

April 24, 2025

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A single molecule elevates solar module output and stability

by Sophie Jenkins

London, UK (SPX) Apr 24, 2025

A new molecule developed through international collaboration has been shown to significantly improve both the performance and durability of perovskite solar cells, according to a recent study published in *Science*. The discovery centers on a synthetic ionic salt named CPMAC, which originates from buckminsterfullerene (C60) and has been shown to outperform traditional C60 in solar applications.

Researchers from the King Abdullah University of Science and Technology (KAUST) played a key role in the development of CPMAC. While C60 has long been used in perovskite solar cells due to its favorable electronic properties, it suffers from stability issues caused by weak van der Waals interactions at the interface with the perovskite layer. CPMAC was engineered to address these shortcomings.

“For over a decade, C60 has been an integral component in the development of perovskite solar cells. However, weak interactions at the perovskite/C60 interface lead to mechanical degradation that compromises long-term solar cell stability. To address this limitation, we designed a C60-derived ionic salt, CPMAC, to significantly enhance the stability of the perovskite solar cells,” explained Professor Osman Bakr, Executive Faculty of the KAUST Center of Excellence for Renewable Energy and Sustainable Technologies (CREST).

Unlike C60, CPMAC forms ionic bonds with the perovskite material, strengthening the electron transfer layer and thereby enhancing both structural stability and energy output. Cells incorporating CPMAC demonstrated a 0.6% improvement in power conversion efficiency (PCE) compared to those using C60.

Though the gain in efficiency appears modest, the impact scales up dramatically in real-world energy production. “When we deal with the scale of a typical power station, the additional electricity generated even from a fraction of a percentage point is quite significant,” said Hongwei Zhu, a research scientist at KAUST.

Beyond efficiency gains, CPMAC also enhanced device longevity. Under accelerated aging tests involving high heat and humidity over 2,000 hours, solar cells containing CPMAC retained a significantly higher portion of their efficiency. Specifically, their degradation was one third that observed in cells using conventional C60.

Further performance evaluation involved assembling the cells into four-cell modules, offering a closer approximation to commercial-scale solar panels. These tests reinforced the molecule’s advantage in both durability and output.

The key to CPMAC’s success lies in its capacity to reduce defects within the electron transfer layer, thanks to the formation of robust ionic bonds. This approach circumvents the limitations posed by van der Waals forces typical of unmodified C60 structures.

Research Report:C60-based ionic salt electron shuttle for high-performance inverted perovskite solar modules

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Solar Energy

Indonesia says China’s Huayou to replace LGES in EV battery project

Published

4 days ago

April 24, 2025

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Indonesia says China’s Huayou to replace LGES in EV battery project

by AFP Staff Writers

Jakarta (AFP) April 23, 2025

China’s Zhejiang Huayou Cobalt is replacing South Korea’s LG Energy Solution as a strategic investor in a multibillion-dollar project to build an electric vehicle battery joint venture in Indonesia, officials said on Wednesday.

The South Korean company, which was part of a consortium that signed a 142 trillion rupiah ($8.4 billion) “Grand Project” in 2020, announced its withdrawal from the project this week, citing factors including market conditions and the investment environment.

Energy and Mineral Resources Minister Bahlil Lahadalia said LG Energy Solution’s decision would not significantly affect the project, which aims to establish a local electric vehicle battery value chain in Indonesia.

“Changes only occur at the investor level, where LG no longer continue its involvement… and has been replaced by a strategic partner from China, namely Huayou,” Bahlil said in a statement.

“Nothing has changed from the initial goal, namely making Indonesia as the center of the world’s electric vehicle industry.”

Indonesia, home to the world’s largest nickel reserve, has been seeking to position itself as a key player in the global electric vehicle supply chain by leveraging its vast reserve of the critical mineral to attract investments.

The government decided not to move forward with the South Korean company in the project due to the long negotiation process with the firm to realise its investment, Investment Minister Rosan Roeslani said.

Rosan cited Huayou’s familiarity with Indonesia as one of the reasons why the government chose the company to succeed LG Energy Solution.

“Huayou had invested in Indonesia,” Rosan said.

“They have sources to develop the industry going forward.”

LG Energy Solution said in a statement on Tuesday that it will continue to explore “various avenues of collaboration” with the Indonesian government, including in its battery joint venture.

HLI Green Power, a joint venture between LG Energy Solution and Hyundai Motor Group, operates Indonesia’s first electric vehicle battery plant, which was launched in 2024 with a production capacity of up to 10 Gigawatt hours (GWh) of cells annually.

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