Protein-assisted bendable Cu-free anode: Hydroxy-functionalized mesoporous carbon matrix for flexible Li-ion batteries

Several approaches have been proposed for development of a current collector-free bendable energy storage electrode for flexible lithium-ion battery applications, such as construction of a hybrid composite structure and introduction of a simple synthesis procedure. However, a more fundamental strategy is required to achieve a highly bendable electrode using carbonaceous materials. We report a novel strategy for development of a protein-assisted bendable Cu-free anode using a hydroxy-functionalized mesoporous carbon nanofiber (CNF) matrix. Zinc oxide nanoparticles and glutamic acid were used as modification agents during the preparation of CNFs and mesoporous CNF structure with N dopants and rich hydroxy groups (Glu-PCNF). The resultant Glu-PCNF electrode exhibited competitive Li-ion storage capabilities, such as a high specific capacity of 469.87 mAh/g at a current density of 100 mA/g and fast energy storage (113.6 mAh/g at 2,000 mA/g). Moreover, the Glu-PCNF electrode maintained its energy storage performance after 1,000 cycles of bending, which demonstrates its high bendability. Therefore, the Cu-free Glu-PCNF electrode, with a high bendability and competitive energy storage performance, can accelerate the implementation of next-generation electronic devices with wearable and flexible functions.