In Situ Growing BCN Nanotubes on Carbon Fibers for Novel High‐Temperature Supercapacitor with Excellent Cycling Performance

Abstract

communication stations of switching 5G signal are inevitable. In that case, supercapacitors that can work at high temperatures must be explored to expand the application range and improve equipment security. However, studies on the development of high-temperature supercapacitors are few because of several challenges, such as: poor cycling stability of the electrode material at high temperature and low boiling point of the electrolyte. [11][12][13] Therefore, supercapacitors operating at high temperatures impose strict requirements on materials and electrolytes.Carbon-based supercapacitors have elicited extensive attention because of their rapid charge/discharge rate, high electrical conductivity, and good thermostability. [14][15][16][17][18][19][20] Extensive effort has been exerted to obtain high-temperature, carbon-based supercapacitors with improved the performance. For example, Yury et al. reported on wide range of temperature supercapacitors based on active carbon (AC). By adjusting the size and shape of AC, the double-layer capacitors could be operated in a wide range of temperature from −100 to 60 °C. [21] Bao et al. reported an all-solid-state planar with activated graphene as the cathode; the planar showed excellent electrochemical performance and safety at 80 °C. [22] However, the cycling stability was unsatisfactory, and the inherent low energy density of pure carbon resulted in a limited application. Motivated by this challenging issue, researchers have conducted studies to improve the electrochemical property. Recent research has shown that the doping of nitrogen (N), boron (B), phosphorus (P), sulfur (S), and fluorine (F) heteroatoms in carbon frame can improve the stability and energy density of carbon materials. [23][24][25][26][27] For example, Feng et al. reported graphene aerogels with N and B doping; the aerogels showed an enhanced energy density of 8.65 W h kg −1 and improved cycling stability close to 100% after 1000 cycles. [28] Our previous work also proved that the introduction of B and N can alter the electrostatic attraction of materials, thereby expanding the operating voltage window to 4.8 V and resulting in a high energy density of 200 Wh kg −1 . [29] Furthermore, the inserted B and N in C lattice structures can effectively improve the charge density and activate the C electron around B and N. [30] Carbon nanomaterials have elicited much research interest in the energy storage field, but most of them cannot be used at high temperatures. Thus, a supercapacitor with high energy and desired stability at high temperatures is urgently required. Herein, BCN nanotubes (BCNNTs) with excellent performance at high temperatures are generated on carbon fibers by optimizing the ratio of B and N. The nanotubes' morphology can effectively alleviate the structural damage caused by the rapid adsorption/ desorption of the electrolyte during long-time charge/discharge cycles at high temperatures, thus improving the high-temperature cycle stability. The symmetric supercapacitors that are assembled with...

Wide-Temperature-Range Flexible Micro-Supercapacitors Using Liquid Crystal Gel Electrolyte

“…Energy storage devices, as energy supplies, have played indispensable role in electronics. With the prosperous development of the Internet of Things, electric vehicles, wearable electronics, aerospace industry, flexible energy storage devices, which require nonplanar surfaces, operating under various harsh environments and high temperatures, have attracted tremendous attention. − Supercapacitors, as energy storage devices, are drawing more and more interest with a major focus on devices featuring high power density, long lifespan, being safer than batteries at high operating temperatures, fast charging time, and good adaptability to complex environments. − Furthermore, faced with the increasing demands for miniaturized, portable, and flexible energy storage systems for wearable devices, electronic skin, and implantable devices, flexible micro-supercapacitors (MSCs) have been extensively investigated. − …”

“…Even though the performance of the symmetric MSCs has been substantially enhanced, there is still room for improvement. Meanwhile, it is well-established that the operating temperature affects the supercapacitors’ performance. ,− Therefore, the influence of temperature on MSC operation should be further explored to expand the application fields of micro-energy storage devices.…”

Vacancy-modified few-layered GaN crystal for novel high-temperature energy storage

“…6 Therefore, it is necessary to explore suitable electrodes to match ILs for alleviating the above problems of ILs based SCs. Currently, carbon materials are used as the main research electrode materials for high-temperature electrochemical energy storage devices, 10,11 based on their large specic surface area, high electrical conductivity, and chemical stability. 12 However, when the temperature is higher than 100 C, strong electrolyte convection breaks the structure of the electrode materials.…”

Thiosalicylic Acid Modified Graphene Aerogel as Efficient Electrode Material for Ionic Liquid Electrolyte-Based Supercapacitors

“…The employment of organic electrolytes can widen the operation voltage window up to 2.5–2.7 V, but their flammable nature may bring about the safe risk of supercapacitors. Alternatively, ionic liquids are an intriguing selection as the electrolyte for supercapacitors because of their nonflammability, higher decomposition voltage (3.5–4.0 V), and wide liquid range. , Besides, the ionic feature of ILs facilitates high ionic conductivity; therefore, IL electrolytes can substantially enhance the energy density of supercapacitors, which is a feasible way to narrow the gap between batteries and supercapacitors based on aqueous/organic electrolytes. For 1-butyl-3-methylimidazolium bis­[(trifluoromethyl)­sulfonyl]­imide ([Bmim]­[Tf 2 N]) ionic liquid, the −C 4 H 9 alkyl chain of Bmim + and the −CF 3 groups of Tf 2 N – are prototypical nonpolar moieties.…”