Highly flexible LiNi0.5Co0.2Mn0.3O2-based cathode for lithium-ion batteries enabled by nanocellulose binder

Because of the rapid evolution of wearable electronics, flexible energy storage devices which allow conformal integration into deformable systems have a high demand to be alternatives to conventional rigid systems. As the dominating energy store devices, lithium ion battery has the advantage of high energy density. However, it could not provide good flexibility. One key reason is that polyvinylidene fluoride (PVDF) is used as the binder in the electrode of the lithium ion battery. In this project, a new kind of binder nanocellulose was introduced to replace PVDF. The free-standing electrode films based on nanocellulose and CNTs were fabricated through vacuum filtration. Compared with the electrodes of the conventional Li-ion batteries, the newly-developed electrodes maintained electrochemical properties and showed better mechanical performance. The existence of nanocellulose enhances the dispersion of active materials leading to higher capacity and stable performance. It could deliver a higher specific capacity of 135.9 mAh g-1 increased by 35.3 mAh g-1 compared with PVDF-based electrodes providing 100.6 mAh g-1. After 100 cycles at 1 C, a capacity of 97.6 mAh g-1 could be achieved by electrodes with nanocellulose. Moreover, assembled into full cells, NC-based lithium ion batteries, stable output is provided and in a circuit lighting LED, no dimming of the light is observed under dynamic conditions of the battery.Bachelor of Engineering (Materials Engineering