Mechanical, electrical and microstructural characterisation of multifunctional structural power composites

Abstract

Multifunctional composites which can fulfil more than one role within a system have attracted considerable interest. This work focusses on structural supercapacitors which simultaneously carry mechanical load whilst storing/delivering electrical energy.Critical mechanical properties (in-plane shear and in-plane compression performance) of two monofunctional and four multifunctional materials were characterised, which gave an insight into the relationships between these properties, the microstructures and 2 fracture processes. The reinforcements included baseline T300 fabric, which was then either grafted or sized with carbon nanotubes, whilst the baseline matrix was MTM57, which was blended with ionic liquid and lithium salt (two concentrations) to imbue multifunctionality. The resulting composites exhibited a high degree of matrix heterogeneity, with the ionic liquid phase preferentially forming at the fibres, resulting in poor matrix dominated properties. However, fibre dominated properties were not depressed. Thus it was demonstrated that these materials can now offer weight savings over conventional monofunctional systems when under modest loading.

Promising Trade‐Offs Between Energy Storage and Load Bearing in Carbon Nanofibers as Structural Energy Storage Devices

“…CFs have typical strength of 3–6 GPa and modulus of 200–300 GPa. CF‐based structural energy storage has excellent mechanical properties 2a,14. However, most CF‐based structural supercapacitors have low capacitance due to low SSA 2a,14b,c.…”

“…CF‐based structural energy storage has excellent mechanical properties 2a,14. However, most CF‐based structural supercapacitors have low capacitance due to low SSA 2a,14b,c. For instance, CFs activated with KOH with single fiber strength up to 3960 MPa were used in structural supercapacitors, but a relatively low SSA of 21.3 m 2 g −1 (compared to over 2000 m 2 g −1 for graphene) and a low capacitance of 2.63 F g −1 were achieved 14c.…”

Recent development and challenges of multifunctional structural supercapacitors for automotive industries

“…Accordingly, it is a leading candidate for novel structural supercapacitor electrodes [27,28]. A structural supercapacitor has two CF electrodes separated by a GF separator [30]. A structural supercapacitor has two CF electrodes separated by a GF separator [30].…”

“…In conventional capacitors, there are two electrodes separated by one separating medium that is electronically non-conductive but ionically conductive, that is, ions can transfer from one side to the other [29]. A structural supercapacitor has two CF electrodes separated by a GF separator [30]. The matrix, which is critical to the capacitor, is a solid polymer electrolyte (SPE) that provides both mechanical and electrical properties.…”

Crash analysis of a conceptual electric vehicle with a damage tolerant battery pack

“…Relevant material and system level solutions have been demonstrated, e.g. [3,4,5,6,8,7,9,10,11]. Alternatively, a combination of electrical energy storage and mechanical impact mitigation capacity can be envisioned.…”