Department of Mechanical and Industrial Engineering, Northeastern University, 360 Huntington Avenue, Boston, MA, 02115, USA.
Mechanical Engineering Department, Mississippi State University, 224 Carpenter building, Mississippi State, MS, 39762, USA.
Adv Mater. 2019 Apr;31(14):e1807313. doi: 10.1002/adma.201807313. Epub 2019 Feb 13.
Batteries constructed via 3D printing techniques have inherent advantages including opportunities for miniaturization, autonomous shaping, and controllable structural prototyping. However, 3D-printed lithium metal batteries (LMBs) have not yet been reported due to the difficulties of printing lithium (Li) metal. Here, for the first time, high-performance LMBs are fabricated through a 3D printing technique using cellulose nanofiber (CNF), which is one of the most earth-abundant biopolymers. The unique shear thinning properties of CNF gel enables the printing of a LiFePO electrode and stable scaffold for Li. The printability of the CNF gel is also investigated theoretically. Moreover, the porous structure of the CNF scaffold also helps to improve ion accessibility and decreases the local current density of Li anode. Thus, dendrite formation due to uneven Li plating/stripping is suppressed. A multiscale computational approach integrating first-principle density function theory and a phase-field model is performed and reveals that the porous structures have more uniform Li deposition. Consequently, a full cell built with a 3D-printed Li anode and a LiFePO cathode exhibits a high capacity of 80 mA h g at a charge/discharge rate of 10 C with capacity retention of 85% even after 3000 cycles.
通过 3D 打印技术构建的电池具有内在的优势，包括微型化、自主成型和可控结构原型制作的机会。然而，由于打印锂（Li）金属的困难，尚未报道 3D 打印的锂金属电池（LMB）。在这里，首次通过使用纤维素纳米纤维（CNF）的 3D 打印技术制造出高性能的 LMB，CNF 是最丰富的生物聚合物之一。CNF 凝胶的独特剪切变稀特性可实现 LiFePO 电极和 Li 稳定支架的打印。还从理论上研究了 CNF 凝胶的可打印性。此外，CNF 支架的多孔结构还有助于提高离子可及性并降低 Li 阳极的局部电流密度。因此，抑制了由于不均匀的 Li 电镀/剥离而导致的枝晶形成。进行了多尺度计算方法的集成，包括第一性原理密度泛函理论和相场模型，结果表明多孔结构具有更均匀的 Li 沉积。因此，由 3D 打印 Li 阳极和 LiFePO 阴极构建的全电池在 10C 的充放电速率下具有 80 mA h g 的高容量，即使在 3000 次循环后容量保持率仍为 85%。
