Triboelectric phenomena can be observed everywhere; however, they are consistently omitted from applications. Although almost all substances exhibit a triboelectrification effect in daily life, chemists as well as materials scientists have performed extensive investigations in both the aspects of basic science and practical applications to promote the development of triboelectric nanogenerators (TENGs). Here, a detailed survey of materials engineering for high triboelectric performance and multifunctional materials toward specific applications is summarized, including constructing micro/ nanostructures, chemically modifying the frication surface, modulating bulk friction materials, the mechanism for improved performance, and preparing materials for implantable medical devices, bionic skin, and wearable electronic devices. Moreover, an in depth discussion of the current challenges and future efforts for strengthening the performance of TENGs is elaborated in detail, which will better guide new researchers toward a deeper understanding of and explorations about TENGs.urgently needed to alleviate a more severe energy crisis, which has diverted extensive attention toward renewable energy (solar energy, geothermal energy, etc.) by virtue of its large quantity and ubiquitous existence in our environment. [1][2][3][4][5][6][7][8][9] In addition, the rapid development of science and technology has also suggested higher requirements for energy delivery. In the past few decades, large numbers of mobile communication electronics, smart wearable devices, and internet of things (IoT) devices based on tens of thousands of sensors have appeared in every corner of the globe. These electronic devices are usually characterized by requiring a small amount of power, only on the microwatt or even the milliwatt level, whereas they hold a relatively large shape to facilitate frequent charging or battery replacement for embedded traditional solid-state power sources. It is, therefore, desirable to integrate an energy harvester together with a battery to form a self-powered system that could be recharged by absorbing and transferring external fragmental energy. Furthermore, considering that a majority of these electronic devices are closely contacting the human body, the individualization of the energy-supply mode related to the person itself remains to be studied in depth.To tackle energy shortages and content-specific power supply requirements, researchers have designed a diversity of energyconversion devices derived from assorted working principles to collect energy, such as solar cells, electromagnetic generators, thermoelectric generators, piezoelectric nanogenerators, and triboelectric nanogenerators (TENGs). [10][11][12][13][14][15][16][17][18][19][20][21] Primarily benefiting from their light weight, low cost, multiple structures, extensive material selection, and even great efficiency at low operating frequencies, the novel TENGs have been proven as up-and-coming candidates to complementarily solve the energy-deficiency issue. T...

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