For thermochemical energy storage, I recommend that you read about use of solar thermal integrated with ammonia reaction. For a starting point, please visit the website of the Australian National University (ANU) as they have done lots of research in this area.

The idea here is that the solar thermal energy is used to decompose NH3 into N2 and H2 and these gases can be stored. This decompostion reaction is endothermic. When needed, the N2 and H2 are combined to for NH3. This reaction is exothermic and releases heat. The released heat can then be used to boil water into steam which turns turbines to generate electricity.

Hope this helps answer your question.

Professor Yehia Khalil, Yale University, USA

Fellow of the University of Oxford, United Kingdom

Dear Enrico,

that this a far common question.

For example please see the links.

There is a lot of Information about 'thermochemical energy storage' research and development in Europe and Australia as well as on the appropriate technologies.

You may 'google' by yourself; there is a lot of stuff.

Good luck

https://energy.gov/sites/prod/files/2014/01/f6/tces_workshop_2013_sattler.pdf

https://www1.eere.energy.gov/solar/pdfs/tces_workshop_2013_lovegrove.pdf

http://www.bentham-open.com/contents/pdf/TOREJ/TOREJ-4-42.pdf

http://ac.els-cdn.com/S1876610212015548/1-s2.0-S1876610212015548-main.pdf?_tid=1e158d7c-d424-11e6-a5c2-00000aab0f26&acdnat=1483716407_619c2bdbb5deacaf802b0ccc809cb5f3

http://ijlct.oxfordjournals.org/content/8/2/106.full

You may also find useful: J. Jensen, "Energy Storage", Ann Arbor Science ─ Butterworth & Co, 1980 (reprinted: 1982), pp. 23-47.