The sun’s energy is difficult to get a hold of – and even more difficult to hold on to. Now chemists have developed molecules with the capacity to create and store substantial amounts of solar energy that may also be released on demand. This is after research by Anders Bo Skov, a master’s student collaborating with the University of Copenhagen’s (UCPH) Center for Exploitation of Solar Energy.

Until recently, storage of solar energy has proven fickle and troublesome: the stubborn molecules would offer only slight enhancements in storage capacity, without increasing the length of storage time as desired. However, now they have been able to shed light on the molecular mystery that had remained experimentally elusive, according to Anders Bo Skov:

“The problem has always been that the energy couldn’t be stored for a long enough time, and not enough could be stored for it to be viable. My system can store energy for years without losing a significant amount of energy. There was a parent system, which had the properties of 100kJ/kg and the energy could be stored for a few days. My new system is better because the energy can be stored at 250kJ/kg for 114 years,” he says to the University Post.

Need key to release energy

The entire research team, run by Professor Mogens Brøndsted Nielsen, works with the so-called Dihydroazulene-Vinylheptafulvene (DHA/VHF) molecular system, which effectively stores energy by changing shape. The system works by undergoing photoconversion between the yellow molecule DHA and the red VHF. This recent success has boosted the group’s efforts to increase the energy of this system.

Anders Bo Skov is doing his master’s at the University of Copenhagen

Despite having found a way to enhance the storage time, Skov says they still have their sights set on improvement:

“We need the key to release the energy. So far we can only store it for 114 years. We want to make energy stored in VHF much less stable than DHA, so that VHF will release the energy. I’m working on different ways to make DHA more stable. We have the goal to double the amount to 500kJ/kg.”

Breaks down into ‘chamomile flower’ component

The breakthrough also has the potential for lessening the hazardous impact of technology and creating greater environmental efficiency.

Lithium batteries, which are composed of harmful acids, bases, and poisonous metals, are a commonplace in electronics today, especially mobile phones. The positive potential of Skov’s system is that it offers a way to gather and store solar energy without carbon dioxide and other toxic byproducts. In this way, there is an opportunity to develop this system into something applicable to energy consumers, offering sustainable solar energy.

“So, we want to use it for solar heat batteries. All batteries today are toxic to the environment while this system is powered only by sunlight and is completely non-toxic to the environment. When it breaks down, [my molecule] turns into a component similar to that found in chamomile flowers,” Skov says.

universitypost@adm.ku.dk

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