Hybrid energy cell for simultaneously harvesting wind, solar, and chemical energies Yingchun Wu 1 , Xiandai Zhong 1 , Xue Wang 1 , Ya Yang 1 (  ), and Zhong Lin Wang 1,2 (  ) 1 Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 100083, China 2 School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0245, USA Received: 21 May 2014 Revised: 15 June 2014 Accepted: 23 June 2014 © Tsinghua University Press and Springer-Verlag Berlin Heidelberg 2014 KEYWORDS hybrid energy cell, wind energy, solar energy, triboelectric nanogenerators, electrochemical cells ABSTRACT We report a hybrid energy cell that can simultaneously or individually harvest wind, solar, and chemical energies to power some electronic devices. By utilizing the wind driven relative rotations between a polytetrafluoroethylene film and an etched Al film attached on two acrylic tubes, the fabricated triboelectric nanogenerator (TENG) can deliver an open-circuit voltage of about 90 V, a short-circuit current density of about 0.5 mA/m 2 , and a maximum power density of 16 mW/m 2 , which is capable of directly lighting up 20 blue light- emitting-diodes (LEDs). By integrating a TENG, a solar cell, and an electrochemical cell, a hybrid energy cell has been fabricated to simultaneously scavenge three different types of energies. As compared with the individual energy units, the hybrid energy cell exhibited much better performance in charging a capacitor. Moreover, we also demonstrated that the hybrid energies generated can be stored in a Li-ion battery for powering a commercial wind speed sensor and a temperature sensor. This work represents significant progress toward practical applications of hybrid energy cells, providing potential solutions for simul- taneously scavenging wind, solar, and chemical energies. 1 Introduction Harvesting wind, solar, and chemical energies from the environment have attracted increasing attention in the past decade due to the growing energy crisis and global warming [1–3]. However, these energies are not always available at the same time, depending on the light, the weather, and other conditions. The purpose of developing hybrid energy cells is to simultaneously/individually harvest these energies by designing an integrated device [4–6], so that the devices can utilize whatever type of energy is available [7]. Although some hybrid energy cells for harvesting two kinds of energies have been demonstrated, there has been no report of a hybrid energy cell that can simultaneously scavenge wind, solar, and chemical energies. It is necessary to simultaneously scavenge these energies to realize the maximum utilization Nano Research 2014, 7(11): 1631–1639 DOI 10.1007/s12274-014-0523-y Address correspondence to Ya Yang, yayang@binn.cas.cn; Zhong Lin Wang, zlwang@gatech.edu