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Abstract：
The utilization of biobased materials for the fabrication of naturally derived ion-exchange membranes is breezing a path to sustainable separators for polymer electrolyte fuel cells (PEFCs). In this investigation, bacterial nanocellulose (BNC, a bacterial polysaccharide) and lignosulfonates (LS, a by-product of the sulfite pulping process), were blended by diffusion of an aqueous solution of the lignin derivative and of the natural-based cross-linker tannic acid into the wet BNC nanofibrous three-dimensional structure, to produce fully biobased ion-exchange membranes. These freestanding separators exhibited good thermal-oxidative stability of up to about 200 °C, in both inert and oxidative atmospheres (N2 and O2, respectively), high mechanical properties with a maximum Young\'s modulus of around 8.2 GPa, as well as good moisture-uptake capacity with a maximum value of ca. 78% after 48 h for the membrane with the higher LS content. Moreover, the combination of the conducting LS with the mechanically robust BNC conveyed ionic conductivity to the membranes, namely a maximum of 23 mS cm-1 at 94 °C and 98% relative humidity (RH) (in-plane configuration), that increased with increasing RH. Hence, these robust water-mediated ion conductors represent an environmentally friendly alternative to the conventional ion-exchange membranes for application in PEFCs.
摘要：
利用生物基材料制造天然衍生的离子交换膜为聚合物电解质燃料电池（PEFC）的可持续隔板开辟了道路。在这次调查中,细菌纳米纤维素(BNC，细菌多糖)和木质素磺酸盐(LS，亚硫酸盐制浆过程的副产品)，通过将木质素衍生物和天然基交联剂单宁酸的水溶液扩散到湿的BNC纳米纤维三维结构中混合，生产完全生物基离子交换膜。这些独立式隔板具有高达约200°C的良好热氧化稳定性，在惰性和氧化性气氛中（分别为N2和O2），高机械性能，最大杨氏模量约为8.2GPa，以及良好的吸湿能力，最大值约为78%后48h为LS含量较高的膜。此外，导电LS与机械坚固的BNC的组合将离子电导率传输到膜，即在94°C和98％相对湿度（RH）下最大23mScm-1（面内配置），随着RH的增加而增加。因此，这些坚固的水介导的离子导体代表了用于PEFC的常规离子交换膜的环境友好的替代方案。
