Lignin-fatty acid hybrid nanocapsules for scalable thermal energy storage in phase-change materials

DOI: 10.1016/j.cej.2020.124711

Authors: Mika H. Sipponen (Aalto University; Stockholm University) , Alexander Henn (Aalto University) , Paavo Penttilä (Aalto University) , Monika Österberg (Aalto University)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Chemical Engineering Journal

State: Published (Approved)
Published: March 2020
Diamond Proposal Number(s): 24748

Abstract: Development of affordable thermal energy storage (TES) has been hampered by the lack of environmentally benign and scalable phase-change materials (PCM). Here we show size-controlled colloidal synthesis of fatty acid-lignin hybrid nanocapsules and demonstrate their applicability as PCM in dry and wet states. The one-pot fabrication allowed for facile preparation of hybrid capsules with a predictable concentration of tall oil fatty acid, oleic acid, or lauric acid in core-shell particles stabilized by softwood kraft lignin. Phase-change peaks of capsules containing 40 wt-% of lauric acid were observed in aqueous dispersion, indicating a possibility to develop colloidal TES systems. In dry form, the hybrid capsules prevented fragmentation of the phase-change peaks during 290 heating-cooling cycles, while in wet state the capsules appeared stable for 25 cycles. The nanoscaled morphology of the capsules was characterized using thermoporometry-differential scanning calorimetry (tp-DSC), transmission electron microscopy (TEM), atomic force microscopy (AFM), dynamic light scattering (DLS), and small angle X-ray scattering (SAXS). Extraction of lauric acid from the capsules allowed for investigation of the intraparticle space previously occupied by the fatty acid. The fatty acid-deficient nanocapsules were found to contain an internal volume that was 19 times as high as that of lignin nanoparticles. Approximately 20 nm thick lignin shells of the capsules were found to be readily accessible to water, permitting heat transfer across the capsules. The possibility to tailor the hybrid capsules by altering the chain length and saturation degree of the fatty acids opens applications that extend beyond the TES systems.

Journal Keywords: colloidal lignin particles; lignin nanoparticles; nanocomposite; thermal energy storage; hybrid material engineering

Subject Areas: Materials, Chemistry, Energy


Instruments: B21-High Throughput SAXS

Added On: 17/03/2020 11:31

Documents:
1-s2.0-S1385894720307026-main.pdf

Discipline Tags:

Energy Storage Earth Sciences & Environment Sustainable Energy Systems Energy Climate Change Energy Materials Chemistry Materials Science Chemical Engineering Engineering & Technology

Technical Tags:

Scattering Small Angle X-ray Scattering (SAXS)