Multisource energy conversion modes in minimally altered plants with soft epicuticular coatings
Abstract Living plants have recently been exploited for unusual tasks such as energy conversion1–6 and environmental sensing.7–12 Yet, using plants as small-scale autonomous energy sources1–5 was obstructed by insufficient power outputs for steadily driving even low-power electronics. Moreover, multicable and -electrode installations on the plants made a realization challenging. Here, we show that plants, by a minimal modification of the leaf epicuticular region and by exploiting their intrinsic circuitry, can be transformed into cable-free, fully plant-enabled integrated systems for multisource energy conversion. In detail, leaf contact electrification caused by wind-induced inter-leaf tangency was magnified by a transparent elastomeric coating on one of two interacting leaves for converting wind energy into harvestable electricity. Further, augmentation of the power output is achieved by coupling multi-frequency band radio frequency (RF) energy conversion modes using the same plant as an unmatched Marconi-antenna. In combination, we observed up to 1100 % enhanced energy accumulation respective to single source harvesting and a single plant like ivy could power a commercial sensing platform wirelessly transmitting environmental data. This shows that living plants could autonomously supply application-oriented electronics while maintaining the positive environmental impact13 by their intrinsic benefits such as O2 production, CO2 fixation, self-repair, and many more extremely difficult (if at all possible) to realize in artificial harvesters.