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[Picture <a href="http://nocamels.com/2014/11/the-worlds-first-smart-hat-sets-bar-high-for-wearable-sports-technology/">source</a>]

There has been rise in demand for electronic wearables (for example measuring athletic performance) but they all have experienced major technological obstacle which is the absence of efficient, durable and comfortable power source. So far, there have been many attempts to design thermocells which would be integrated into clothing. Semiconductor-based thermoelectric generators have proven to be very costly, fragile and provide too little power. While thermocells based on electrolyte solutions are very troublesome to incorporate into complex <a href="https://en.wikipedia.org/wiki/Wearable_computer.">wearables</a>.

The researchers at Huazhong University of Science and Technology in China have finally <a href="http://onlinelibrary.wiley.com/doi/10.1002/anie.201606314/abstract">discovered</a> an answer to this problem. They have designed thermocells which include gel-based electrolytes capable of generating enough power to sustain popular wearables.
Scientists applied thermogalvanic effect in order to produce current - two electrodes are kept at different temperatures in contact with an electrolyte gel. This potential difference produces an electric current. 

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[Picture <a href="http://eu.wiley.com/WileyCDA/PressRelease/pressReleaseId-127782.html/">source</a>]

The researchers created two kinds of cells consisting different redox pairs (redox pair is an electron donor and its corresponding oxidized acceptor form). Each cell consisted two electrodes, which were small metal plates and electrolyte gel between them.  
In the next step, these cells positioned in checkerboard like pattern. This checkerboard was incorporated into a glove that transformed body heat into electric current to generate power. Due to application of electrolyte gel, the whole device is flexible and robust.

The research has been recently published in peer-reviewed scientific journal <a href="http://onlinelibrary.wiley.com/doi/10.1002/anie.201606314/abstract">Angewandte Chemie</a>.

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References:

Angewandte Chemie, August 2016 - <a href="http://onlinelibrary.wiley.com/doi/10.1002/anie.201606314/abstract">Wearable Thermocells Based on Gel Electrolytes for the Utilization of Body Heat</a>.

Tech Radar article - <a href="http://www.techradar.com/news/wearables/body-heat-alone-is-enough-to-power-wearable-technology-1328052">"Body heat alone is enough to power wearable technology"</a>.

Wikipedia article - <a href="https://en.wikipedia.org/wiki/Wearable_computer">"Wearable computer"</a>.