PhD student, University of Cambridge
I am a first-year PhD candidate investigating the use of thermoelectric nanomaterials in energy harvesting applications. Thermoelectric devices, which can convert heat into electricity, have enormous potential in thermal energy harvesting. Recent progress in higher efficiency thermoelectric materials can be attributed to nanoscale enhancement. Physically, nanostructured thermoelectric enhancement aims to split the interdependence of the electrical and thermal transport, allowing for greater optimization of the thermoelectric properties. One consequence of nanostructuring is the increase of interfaces since interface scattering of phonons and charge carriers plays an important role in the understanding and control of the physical mechanisms behind this enhancement. Furthermore, low-dimensional materials have been stipulated to be the way forward towards achieving high values of electrical conductivity, while not compromising on thermal conductivity.
In this regard, 2D thermoelectric nanomaterials offer tremendous scope in terms of tuning the contributions of the thermal and electronic carriers in the system, and organic thermoelectric materials are flexible, relatively easy and cheap to fabricate. Thus, using these materials in hybrid thermoelectric structures would pave the way for novel materials with enhanced thermoelectric properties for next-generation thermoelectric generators.
My previous work on piezoelectric nanomaterials for energy harvesting has been published in ACS Appl. Mater. Interfaces, Macromol. Mater. Eng. and Adv. Funct. Mater. And those similar growth techniques amongst new ideas will be applied to thermoelectric nanomaterials nanofabrication routes during my PhD. The project has particularly wide-ranging impact in the energy generation field through the development of novel thermoelectric materials, through innovative fabrication processes, and the subsequent optimisation of thermoelectric devices. In addition, it has implications for the field of solid-state cooling through the converse Peltier effect.
Abstract: Transparent, conductive electrodes are important in many applications such as touch screens, displays and solar cells. Transparent energy storage systems will require materials that can simultaneously act as current collectors and active storage media. This is challenging as it means improving the energy storage capability of conducting materials while retaining transparency. Here, we have used aerosol-jet spraying strategy to prepare transparent supercapacitor electrodes from ruthenium oxide/poly(3,4-ethylenedioxythiophene): poly(styrene-4-sulfonate), (RuO2/PEDOT: PSS) hybrid thin films. These films combine excellent transparency with reasonably high conductivity (DC conductivity =279 S/cm) and excellent volumetric capacitance (CV =190 F/cm3). We demonstrate electrodes with historical high transparency of 93% which display an areal capacitance of C/AC/A=1.2 mF/cm2, significantly higher than the rest reported electrodes with comparable transparency. We have assembled flexible, transparent, solid-state symmetric devices which exhibit T =80% and C/AC/A=0.84 mF/cm2 and are stable over 10,000 charge/discharge cycles. Asymmetric solid-state device with RuO2/PEDOT: PSS and PEDOT: PSS thin films as positive and negative electrodes, respectively, display an areal capacitances of 1.06 mF/cm2, a maximum power density (P/A)(P/A) of 147 μW/cm2 and an energy density (E/A)(E/A) of 0.053 μWh/cm2. Furthermore, large area transparent solid-state supercapacitor device has been built. We believe the solution-processed transparent films could be easily scaled-up to meet the industrial demands.
Pub.: 27 Aug '16, Pinned: 29 Jun '17
Abstract: Inkjet and aerosol jet printing have recently emerged as promising fabrication techniques for a broad range of devices for electrochemical energy conversion and storage – batteries, fuel cells, and supercapacitors. If fully realized, these printing techniques may enable device performance advantages accruing from precise micron scale patterning, thin layer deposition, and materials grading. Printing may also allow scalable, low materials waste manufacturing, and conformal integration of power elements into structural elements. This article reviews the fundamental capabilities of inkjet and aerosol jet printing relevant to electrochemical devices, surveys current literature, and presents future challenges which must be tackled to achieve high performance, printed electrochemical energy storage, and conversion devices.
Pub.: 31 Mar '17, Pinned: 29 Jun '17