3D interconnected macrostructure based on nano-scale pyroprotein units for energy storage. (20th December 2016) - Kim, Na Rae
Graphical abstract: 3D interconnected pyroprotein macrostructures (3D-IPMs) were fabricated from silk proteins using a simple templated sol-gel method followed by heating with potassium hydroxide. The resulting materials exhibit outstanding electrochemical performance. Highlights: 3D interconnected pyroprotein macrostructures (3D-IPMs) are fabricated. 3D-IPMs have well-developed pore structures and numerous redox-active nitrogen atoms. 3D-IPMs exhibit high capacities of ∼680 mA h g −1 and great rate/cycling performances. High energy (142.7 Wh kg −1 ) and high power (23, 850 W kg −1 ) are achieved. Abstract: A porous carbon monolith with a well-defined internal nanostructure consisting of highly redox-active materials has potential as an electrode in energy storage applications. In this study, 3D interconnected pyroprotein macrostructures (3D-IPMs) were fabricated from silk proteins using a simple templated sol-gel method and subsequently heated with potassium hydroxide. The resulting 3D-IPMs, which were further optimized, had high nitrogen concentrations (C/N ratio: 11.4), good electrical conductivities of ∼2.8 S cm −1, and well-developed pore structures. The 3D-IPMs showed reversible storage capacities of ∼680 mA h g −1 at 0.1 A g −1 via a pseudocapacitive Li ion storage mechanism in the anodic potential range. Even when a 300-fold larger current rate was used, a reversible capacity of ∼230 mA h g −1 was maintained. In addition, the 3D-IPMs exhibited remarkable stability over the course of 1, 000 cycles. The practicability of 3D-IPM-based energy storage devices was demonstrated by assembling full cells with a well-known cathode material. The full cell devices delivered a specific energy of 142.7 W h kg −1 at 190 W kg −1 and specific power of 23, 850 W kg −1 at 48.1 W h kg −1 . In addition, their performance remained stable across many cycles.