Xu Hang, Jiang Kezhu, Zhang Xueping, Zhang Xiaoyu, Guo Shaohua, Zhou Haoshen
Center of Energy Storage Materials & Technology, College of Engineering and Applied Sciences, Jiangsu Key Laboratory of Artificial Functional Materials, National Laboratory of Solid State Microstructures, and Collaborative Innovation Center of Advanced Microstructure , Nanjing University , Nanjing 210093 , China.
National Institute of Advanced Industrial Science and Technology (AIST) , Umezono 1-1-1 , Tsukuba 305-8568 , Japan.
ACS Appl Mater Interfaces. 2019 Jul 31;11(30):26817-26823. doi: 10.1021/acsami.9b06564. Epub 2019 Jul 18.
Sodium-ion batteries (SIBs) are promising candidates applied to large-scale energy storage systems owing to abundant sodium resources and high economic efficiency. Layered manganese-based oxides as a prevailing cathode for sodium-ion batteries have been extensively studied, where doping or coating has been demonstrated to improve the electrochemical performance. However, the binder that tends to be the popular poly(vinylidene difluoride), is revealed to generate swellability upon cycling, leading to electrode material cracks and disconnection with current collectors. For the above issues, in this work, environmentally friendly sodium alginate is utilized as the aqueous binder in a conventional layered transition-metal oxide cathode P2-NaMnO for SIBs. Through credible comparative experiments, sodium alginate is testified to play an essential role in suppressing cracks on the surface of materials, preventing surge in charge-transfer resistance and restraining detachment between electrode and current collector. Therefore, sodium alginate is proved to be an ideal binder to match with P2-NaMnO, where some issues existed before, as a promising cathode material with excellent performance and low cost. This study displays that improving battery performance by exploring suitable binder systems can equal or even exceed the performance improvement through modification of the material itself, and this perspective of enhancement should not be ignored.
钠离子电池（SIBs）由于钠资源丰富且经济效益高，是应用于大规模储能系统的有前景的候选者。层状锰基氧化物作为钠离子电池的主流正极材料已被广泛研究，其中掺杂或涂层已被证明可改善其电化学性能。然而，常用的聚偏二氟乙烯粘结剂在循环过程中会产生膨胀性，导致电极材料开裂并与集流体分离。针对上述问题，在本工作中，环境友好型海藻酸钠被用作钠离子电池传统层状过渡金属氧化物正极P2-NaMnO的水性粘结剂。通过可靠的对比实验，证明海藻酸钠在抑制材料表面裂纹、防止电荷转移电阻激增以及抑制电极与集流体之间的分离方面起着至关重要的作用。因此，海藻酸钠被证明是与P2-NaMnO相匹配的理想粘结剂，P2-NaMnO作为一种具有优异性能和低成本的有前景的正极材料，之前存在一些问题。本研究表明，通过探索合适的粘结剂体系来提高电池性能可以等同于甚至超过通过材料本身改性所实现的性能提升，这种增强视角不应被忽视。
