“Salt-in-Fiber” Electrolyte Enables High-Voltage Solid-State Supercapacitors

Abstract

The design of functional solid electrolytes is crucial to develop flexible nonsealing supercapacitors for lightweight, wearable, and portable electronics. Herein, an innovative method was used to fabricate LiCl electrospun electrolyte. A solid-state supercapacitor was assembled using LiCl-containing nanofibers as both an electrolyte and separator, and commercial activated carbon as the positive and negative electrodes, respectively. The morphology and chemical composition of the novel electrolyte was revealed using scanning electron microscopy, energy-dispersive X-ray, Fourier transform infrared, and Brunauer–Emmett–Teller analyses. The electrochemical properties of the solid-state supercapacitor were characterized by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy techniques. Additionally, the performance of the supercapacitor device with the nanofiber electrolyte was compared with that of the aqueous electrolyte-based and hydrogel-based devices. The supercapacitor with the LiCl nanofiber electrolyte exhibited an extended potential window of 2.3 V compared to 1.8 V for the aqueous-based device and 2 V for the hydrogel-based device. Consequently, the specific capacitance and energy density were increased by 9.6 and 44.6%, respectively, when both devices are measured at 1 A/g.

Optimized Lithography-Free Fabrication of Sub-100 nm Nb2O5 Nanotube Films as Negative Supercapacitor Electrodes: Tuned Oxygen Vacancies and Cationic Intercalation

“…A plethora of merits qualified supercapacitors (SCs) as leading candidates for high-performance next-generation energy storage devices. − While the energy density of SCs is relatively lower than that of battery devices, asymmetric SC (A-SC) and hybrid SC (H-SC) configurations were purposed to bridge such an energy density gap. − However, there are many debates in the literature concerning the definition of A-SCs and H-SCs. , The A-SC is a device with either two electrodes made of the same material and different mass loadings or two electrodes made of different materials, namely, capacitive and pseudocapacitive, based on their way to store ions/charges. , In contrast, the H-SC is the term used when the device contains one battery-like electrode material. , To this end, the studies targeting high-performance A-SCs and H-SCs are mainly focused on the improvement of the anode materials, with little attention devoted to developing negative electrode materials. − The inefficient performance of either the positive or negative electrode will restrict the full tapped capacitance of the device, limiting the overall device performance. − Noteworthily, more efforts should be directed toward the synthesis and development of functional negative electrode materials. , …”

Novel self-regenerative and non-flammable high-performance hydrogel electrolytes with anti-freeze properties and intrinsic redox activity for energy storage applications

“…This observation can be ascribed to the heating effect, which may cause cross-linking of the polymeric chains which makes it difficult for them to regenerate ideally. 46 To elucidate the stability of the hydrogel under anti-freezing conditions, the C//3-LiBr@PVAM//C device was tested at −20 °C. The GCD curves reveal no differences in behavior at room temperature and freezing temperature, which confirms the stability of the hydrogel under freezing conditions, as shown in Fig.…”

“…This capacitance is almost double the capacitance reported for the same device using different gel electrolytes. 46 Note that the specic capacitance was 34.5 F g −1 at 5 A g −1 , demonstrating an excellent rate capability of 54.3% compared to other gel electrolytes. 46 Moreover, the selfdischarge behavior of the device was investigated by charging the device and then leaving it under OCV conditions while monitoring the change in the OCV with time.…”

“…46 Note that the specic capacitance was 34.5 F g −1 at 5 A g −1 , demonstrating an excellent rate capability of 54.3% compared to other gel electrolytes. 46 Moreover, the selfdischarge behavior of the device was investigated by charging the device and then leaving it under OCV conditions while monitoring the change in the OCV with time. The device revealed a lower self-discharge rate aer 11 000 s compared to those reported in the literature.…”

Binder-free Mn–V–Sn oxyhydroxide decorated with metallic Sn as an earth-abundant supercapattery electrode for intensified energy storage

“…Note that the + and − signs refer to polarization charge. The specific capacitances for the three- and two-electrode systems in F g −1 were calculated from (CV) using eqn (2): 40,41 where C CV is the calculated specific capacitance (F g −1 ), Δ V is the potential window ( V ), ν is the potential scan rate (mV s −1 ), m is the active mass of the electrode material ( g ), and I is the capacitive current ( A ). Due to the non-linear discharge profiles of the as-fabricated composite and the device, the specific capacitances can be obtained using the CED curves by using the integral form of C CED = i × d t /Δ V as depicted by eqn (3): 42,43 where I is the applied current ( A ), is the area under the discharge curve, m is the mass of the active material, and Δ V is the potential window ( V ).…”