Supercapacitors are an alternative to batteries that can charge and discharge very fast. However, preserving this fast-charging capability at low temperatures is challenging. Conventional porous carbon electrodes do not perform well in the cold due to the lowered ion- and charge transport.
Jennifer Q. Lu, University of California, Merced, USA, Yat Li, University of California, Santa Cruz, USA, and colleagues have developed 3D-printed porous carbon aerogels for electrodes in ultralow-temperature supercapacitors, reducing heating needs, e.g., for capacitors used in space or polar missions. The team 3D-printed a porous carbon aerogel in a lattice pattern via a direct ink writing (DIW) method, using an ink based on cellulose nanocrystals and a silica nanosphere suspension. The cellulose nanocrystals act as a carbon precursor and the silica serves as a template for creating pores. After printing, the material was freeze-dried and carbonized, the silica template was removed, and the material was activated using KOH.
The resulting product has multiple levels of pores, from 500-µm pores in its lattice-like structure to nanometer-sized pores within the bars of the lattice. This multiscale porous network provides adequate ion diffusion and charge transfer through the resulting electrode at –70 °C, achieving higher energy storage capacitance than previously reported low-temperature supercapacitors.
- Printing Porous Carbon Aerogels for Low Temperature Supercapacitors,
Bin Yao, Huarong Peng, Haozhe Zhang, Junzhe Kang, Cheng Zhu, Gerardo Delgado, Dana Byrne, Soren Faulkner, Megan Freyman, Xihong Lu, Marcus A. Worsley, Jennifer Q. Lu, Yat Li,
Nano Lett. 2021.