Carbons derived from all-cellulose based composites for energy storage devices

寻找合适的储能材料对于越来越多地使用可再生能源非常重要。纤维素作为最常见的生物聚合物，适用于多种应用，并且是高性能复合材料的有前途的基础。Cellstor的概念是（i）制备由具有不同尺寸（纳米-微米-宏观）和形状（球形vs原纤维）的纤维素材料组成的全纤维素复合材料，（ii）将这些材料转化为活性炭，以及（iii）将这些材料组装成电化学能量存储设备（超级电容器和混合电容器）。已知纤维素材料的热降解行为取决于结晶度、摩尔质量、晶相（纤维素I与II）和形态。尽管该方法可能导致具有优异电化学性能的碳材料，但提供具有上级性能的电化学装置不是该项目的专用目标。该提案的主要目标是了解全纤维素复合材料的结构如何以及在多大程度上影响所形成的碳结构以及随后的电化学性能。因此，焦点在于初始全纤维素复合材料结构与所得碳之间的相关性，以直接合成具有不同特征（如形态和孔结构）的材料。为了优化超级电容器的电化学性能，木质素将被改性并用作水性电解质中的添加剂。

Finding suitable materials for energy storage is very important for a growing use of renewable sources. Cellulose as most common biopolymer is suited for a multitude of applications and a promising basic for high performance composites. The concept of Cellstor is to (i) prepare all-cellulose composites that consist of cellulosic materials having different sizes (nano-micro-macro) and shapes (spheres vs fibrils), (ii) to convert these into activated carbons, and (iii) to assemble these materials into electrochemical energy storage devices (supercapacitors and hybrid capacitors). It is known that the thermal degradation behavior of cellulosic materials depends on crystallinity, molar mass, crystal phase (cellulose I vs II) and morphology. Although the approach may lead to carbon materials with exceptional electrochemical performance, it is not a dedicated objective of the project to provide electrochemical devices with superior properties. The main goal of the proposal is to understand how and to which extent the structure of the all-cellulose composites impacts the formed carbon structures and subsequently the electrochemical performance. The focus therefore lies in the correlation between the initial all-cellulose composite structure and the resulting carbons to directly synthesize of materials with different characteristics as morphology and pore structure. For optimisation of the electrochemical performance of supercapacitors, lignins will be modified and used as additives in aqueous electrolytes.