Cork: Enabler of sustainable and efficient coaxial structural batteries

Mafalda Valente; Sara Magalhães Silva; Maria Helena Braga

doi:10.1016/j.heliyon.2023.e15063

Cork: Enabler of sustainable and efficient coaxial structural batteries

Heliyon. 2023 Apr 8;9(4):e15063. doi: 10.1016/j.heliyon.2023.e15063. eCollection 2023 Apr.

Authors

Mafalda Valente^{1

2

3}, Sara Magalhães Silva^{4

5}, Maria Helena Braga^{2

3

6}

Affiliations

¹ Metallurgical and Materials Engineering Department, Engineering Faculty, University of Porto, R. Dr. Roberto Frias s/n, 4200-465 Porto, Portugal.
² Engineering Physics Department, Engineering Faculty, University of Porto, R. Dr. Roberto Frias s/n, 4200-465 Porto, Portugal.
³ Materials for Energy Research, MaTER Laboratory, Engineering Faculty, University of Porto, R. Dr. Roberto Frias s/n, 4200-465 Porto, Portugal.
⁴ Amorim Cork Composites, R. Comendador Américo Ferreira Amorim 260, 4535-186 Mozelos, Portugal.
⁵ EMaRT Group - Emerging: Materials, Research, Technology, ESAN - University of Aveiro, Estrada do Cercal, 449, 3720-509 Oliveira de Azeméis, Portugal.
⁶ LAETA-INEGI, Institute of Science and Innovation in Mechanical and Industrial Engineering, 4200-465 Porto, Portugal.

Abstract

Structural batteries aim to advance to 'massless' energy storage units. Here we report an electrode-less coaxial battery with a cork-internal shell, CFRP(+)/cork/Cu/Na_2.99Ba_0.005ClO/Al(-), where CFRP is carbon fiber reinforced polymer. The cell may, alternatively, solely have a cork external shell cork/Cu(+)/Na_2.99Ba_0.005ClO/Al(-). Cork is a cellular material with a negative CO₂ footprint, light, elastic, impermeable to gases or liquids, and an excellent thermal insulator. Cork was used tandemly with a CFRP shell, working as the positive current collector to enhance the structural batteries' properties while allowing a giant electrostatic performance in conjunction with the Na⁺ solid-state ferroelectric injected between the Al negative collector and the cork. Cork was shown a polar dielectric. This 'minimalist' cell may perform without copper making the cells even more sustainable. Neither cells contain traditional electrodes, only one or two current collectors. The cells perform from 0 to >50 °C. The maximum capacity of the cork/Cu(+)/Na_2.99Ba_0.005ClO/Al(-) cells is ∼110 mAh.cm^-2 (outer shell) with <I> ≈ 90 μA cm^-2, <V> ≈ 0.90 V, V_max ≈ 1.1-1.3 V, I_max ≈ 108 μA cm^-2, and a constant resistance discharging life (>40 days). The novel family of cells presented may also harvest waste heat and thermal energy at a constant temperature as their potential and current increase with temperature. Conversely, rising potentials boost the cells' temperature, as expected from pyroelectrics, as shown herein.

Keywords: Cork dielectric; Electrode-less batteries; Ferroelectrics; Solid electrolytes; Structural batteries.

Publication types

Review