Integration of Energy Harvesting and Electrochemical Storage Devices

Abstract

and power the building in the night. [12] Such a smart combination not only provides multifunctions, but also saves materials and footprint in modern buildings. Another example is the wireless operation devices such as unmanned aerial vehicles and implantable biosensors, which are required to be placed in remote area or hazardous condition. They are required to be self-charged/powered by converting other energy forms from natural sources (such as heat, solar, and wind) or human movements (via piezoelectric and triboelectric effects) into usable power sources. [16][17][18][19][20] Moreover, the harvested energy needs to be stored electrochemically for backup power. [21][22][23] In this context, multifunctional devices/materials with multiple roles are imperative for the development of future self-powered smart devices.Electrochemical energy storage (EES) system is one of the most important parts in integrated smart devices. [24][25][26][27][28][29][30][31][32][33] The current dominant EES systems include lithium-ion batteries (LIBs) and supercapacitors. [34][35][36][37] The former generally possess high energy density but with relatively low power density, [38][39][40] whereas the latter have the opposite advantage and are typically used for high-power area. [41][42][43][44][45][46] In general, current EES devices require external power source and intensive maintenance. This can be challenging in deserts or other uninhabited areas. In this regard, it becomes quite relevant to develop self-powered smart devices by integrating energy harvest and conversion and storage units. [47] Currently, considerable efforts are being devoted to fabricating integrated/joint systems to combine energy harvesting/ storage components. The harvesting component can capture the energy from surroundings and convert into usable energy to power electrical devices. [28,48,49] For example, Wang and coworkers fabricated a series of self-powered devices (electrochromic devices, water splitting systems, and sensors) driven by piezoelectric nanogenerators and triboelectric nanogenerators. [50][51][52][53][54] Such nanogenerators convert the small magnitude of mechanical energy in our living environment into electricity. In addition, solar cells have also been integrated into electrochromic devices to achieve self-powered operation and to maximize energy saving/utilization. [55,56] Along with multifunction, attentions are also being paid to miniaturized energy systems such as nanosized and fibershaped energy conversion/storage devices. [57][58][59][60][61] Though planar-structured devices have the advantage of simple process and cost effectiveness, they cannot be easily integrated with wearable equipment. Hence, developing new materials that are flexible and stretchable, transparent and conductive, or Multifunctional energy devices with various energy forms in different operation modes are under current research focus toward the new-generation smart and self-powered electronics. In this review, the recent progress made in developing integrated/jo...

Semitransparent Energy‐Storing Functional Photovoltaics Monolithically Integrated with Electrochromic Supercapacitors

“…For this purpose, various types of energy storage systems have been explored, including conventional lithium‐ion batteries, nickel‐metal hybrid batteries, and supercapacitors . In spite of recent attention to integrating the energy harvester with a storage system, most approaches still use wires to connect to external storage devices for simplicity . However, when the distance between two systems is long, the energy storage efficiency is decreased due to larger energy dissipation arising from the internal resistance of the wires .…”

“…[12,13] In spite of recent attention to integrating the energy harvester with a storage system, most approaches still use wires to connect to external storage devices for simplicity. [14,15] However, when the distance between two systems is long, the energy storage efficiency is decreased due to larger energy dissipation arising from the internal resistance of the wires. [16,17] Also, the simple connection of two isolated systems requires more space for installation, which lowers the integration density within a specific area.…”

Advances in the development of power supplies for the Internet of Everything

“…Additionally, various energy storage devices have been developed, such as supercapacitors, secondary ion batteries, metal‐air batteries, metal‐sulfur batteries, redox flow batteries, and other chemical batteries (eg, nickel‐based and zinc‐based batteries). To date, to achieve the purpose of the integration of energy harvesting and storage systems, three connection modes have been proposed (Figure ) that these two systems can be connected via an external circuit or an integrated platform or integrated into one single unit/chip . In Mode I and II, the energy conversion and storage processes are separate and independent, different with Mode III in which the energy is converted and stored simultaneously without any intermediate processes.…”

“…Mode I: integration via extra connections; Mode II: integration via a platform; and Mode III: integration into one single unit. Reproduced with permission . Copyright 2017, Wiley‐VCH…”

Bio‐Waste Derived Carbon as Interlayer and Scaffold for Li‐S Batteries

“…The growing energy demand and the unmanageable carbon emission to the environment urge the development of advanced and high energy density storage devices for modern portable devices to electric vehicles and for renewable energy storage applications . Despite the various advantages of lithium ion batteries that fetch the market attention together with a key component in the emerging smart technology in the recent days, the still demanding high energy and power requirement of modern e‐applications necessitate further research on next generation batteries ,. Particularly, Li−S batteries satisfy most of such requirements owing to their advantages that include low cost, environmentally benign nature, high theoretical capacity (1675 mAh/g) and energy density (2600 Wh/kg), originated from the direct two electron transfer reaction taking place between sulfur and lithium .…”