Stable Na Electrodeposition Enabled by Agarose-Based Water-Soluble Sodium Ion Battery Separators

Abstract

Developing efficient energy storage technologies is at the core of current strategies toward a decarbonized society. Energy storage systems based on renewable, nontoxic, and degradable materials represent a circular economy approach to address the environmental pollution issues associated with conventional batteries, that is, resource depletion and inadequate disposal. Here we tap into that prospect using a marine biopolymer together with a water-soluble polymer to develop sodium ion battery (NIB) separators. Mesoporous membranes comprising agarose, an algae-derived polysaccharide, and poly(vinyl alcohol) are synthesized via nonsolvent-induced phase separation. Obtained membranes outperform conventional nondegradable NIB separators in terms of thermal stability, electrolyte wettability, and Na + conductivity. Thanks to the good interfacial adhesion with metallic Na promoted by the hydroxyl and ether functional groups of agarose, the separators enable a stable and homogeneous Na deposition with limited dendrite growth. As a result, membranes can operate at 200 μA cm –2 , in contrast with Celgard and glass microfiber, which short circuit at 50 and 100 μA cm –2 , respectively. When evaluated in Na 3 V 2 (PO 4 ) 3 /Na half-cells, agarose-based separators deliver 108 mA h g –1 after 50 cycles at C/10, together with a remarkable rate capability. This work opens up new possibilities for the use of water-degradable separators, reducing the environmental burdens arising from the uncontrolled accumulation of electronic waste in marine or land environments.

Hierarchical Nanocellulose‐Based Gel Polymer Electrolytes for Stable Na Electrodeposition in Sodium Ion Batteries

“…However, further increase in CNF content results in drop of the ionic conductivity to 0.672 mS cm -1 , as both the surface functional groups and surface area are the dominant drivers to achieve a large ionic transport. The achieved ionic conductivities are well-above the results reported for other separator-liquid electrolyte systems (1.35 mS cm -1 for agarose/ PVA, [34] 0.12 mS cm -1 for Celgard, [34] 0.4 mS cm -1 for cellulose acetate, [59] or 0.07 mS cm -1 for chitin nanofiber membranes), [60] or most of the GPEs for NIBs developed so far (see Table S3, Supporting Information, for further details).…”

“…[32] Importantly, mesoporous morphologies boost ion transference and ensure uniform ion-flux between the electrodes, providing a stable and reversible ion plating/stripping without dendrite formation. [33][34][35][36] Although structures solely comprising CNCs could be used a priori as GPEs or solid polymer electrolytes for batteries, their mechanical properties are not at par. Improving the mechanical stability of CNC-based materials upon blending with other cellulosic derivatives may ensure a good compatibility between electrolyte partners through van der Waals interactions and intermolecular hydrogen bonding.…”

Environmental Impact Assessment of Na3V2(PO4)3 Cathode Production for Sodium‐Ion Batteries

“…For the sake of clarity, characteristic galvanostatic charge-discharge curves of Na 3 V 2 (PO 4 ) 3 /Na half cells are shown in Figure 3a. [54] Generally, the Na 3 V 2 (PO 4 ) 3 Table 2. Environmental impacts for Na 3 V 2 (PO 4 ) 3 cathode fabrication considering 1 kg of material as FU.…”

Elastic Agarose Nanowire Aerogels for Oil–Water Separation and Thermal Insulation

“…In particular, the gelation process of AG aerogels is a physical process without any chemical crosslinking agents, unlike the gelation of other biobased nanomaterials . To date, AG is more widely used in vitro cartilage tissue engineering, 3D bioprinting, biosensors, disease diagnosis, and drug delivery because of various advantages such as biocompatibility, biodegradability, and abundance. ,,− Although AG hydrogels and aerogels have been extensively used in biomedicine and other fields requiring energy storage, few results have been published about using AG aerogels for oil–water separation or thermal insulation. Because AG aerogels are easily deformed by being touched or squeezed, self-hydrophilicity AG aerogels are unable to achieve selective oil–water absorption.…”