An All-Solid-State Coaxial Structural Battery Using Sodium-Based Electrolyte

Cork: Enabler of sustainable and efficient coaxial structural batteries

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.

Production and Characterisation of Fibre-Reinforced All-Solid-State Electrodes and Separator for the Application in Structural Batteries

The electrification of the air transport sector demands for an energy storage that adds as little volume and weight to the overall system as possible. Regarding this so-called structural battery, composites enable the storage of electrical energy in commonly used load bearing fibre composite structures. A structural battery composite can store electrical energy while bearing mechanical loads, thus reducing parasitic mass and volume. In this study, structural cathodes were prepared by slurry coating carbon fibres with lithium iron phosphate (LFP), polyethylene oxide (PEO), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and carbon black. For the structural anodes, the carbon fibres were utilised as active material and slurry coated with PEO and LiTFSI. These structural electrodes as well as a structural separator were characterised by electrochemical cycling. With 139 mAhgAM−1, the structural cathodes demonstrated good utilisation of the active material. The carbon fibres used in the anode exhibited capacities of up to 92 mAhgAM−1. High irreversible lithium losses were observed, which are attributed to the poor electrolyte wetting behaviour of the carbon fibres. A structural battery demonstrator with a lithium metal anode was realised and reached a maximum specific energy of 64 Whkg−1 with respect to electrode and separator weight.

Designing Versatile Polymers for Lithium-Ion Battery Applications: A Review

Solid-state electrolytes are a promising family of materials for the next generation of high-energy rechargeable lithium batteries. Polymer electrolytes (PEs) have been widely investigated due to their main advantages, which include easy processability, high safety, good mechanical flexibility, and low weight. This review presents recent scientific advances in the design of versatile polymer-based electrolytes and composite electrolytes, underlining the current limitations and remaining challenges while highlighting their technical accomplishments. The recent advances in PEs as a promising application in structural batteries are also emphasized.