TEMPERATURE INFLUENCE ON ELECTRICAL PROPERTIES OF CARBON NANOTUBES MODIFIED SOLID ELECTROLYTE-BASED STRUCTURAL SUPERCAPACITOR

摘要

In the present work, we report on structural supercapacitors which are based on NASICON-type solid electrolyte Li_(1.4)Al_(0.4)Ti_(1.6)(PO_4)_3 (LATP). The nanostructured electrodes incorporate single-wall carbon nanotubes (SWCNTs) mixed with the LATP electrolyte. The complete energy storage devices are manufactured in a sandwich structure consisting of two nanostructured electrode layers which are separated by a pure LATP layer. The as-prepared specimens are embedded in composite materials with Airstone 880/886H epoxy resin as matrix. Their electrical properties are characterized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). At ambient temperature, the addition of 6.5 wt.% SWCNTs results in a distinct improvement by reducing the total resistance of the embedded devices and enhances the capacitance from 0.025 mF g~(-1) to 3.160 mF g~(-1) at a scan rate of 5 mV s~(-1). Electrical measurements of two types of specimens are then applied under different temperatures from ambient temperature to 80°C. It is observed that the equivalent series resistance (ESR) of device with SWCNTs decreases greatly and capacitance increases comparing with the device without SWCNTs. As a conclusion, the structural supercapacitors acquire excellent performance through high efficient double layer effects realized by nanostructured electrode/electrolyte interphase (large surface electrode areas).