Cell-like-carbon-micro-spheres for robust potassium anode

Hongbo Ding; Jiang Zhou; Apparao M Rao; Bingan Lu

doi:10.1093/nsr/nwaa276

Cell-like-carbon-micro-spheres for robust potassium anode

Natl Sci Rev. 2020 Nov 7;8(9):nwaa276. doi: 10.1093/nsr/nwaa276. eCollection 2021 Sep.

Authors

Hongbo Ding¹, Jiang Zhou², Apparao M Rao³, Bingan Lu¹

Affiliations

¹ School of Physics and Electronics, State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082, China.
² School of Materials Science and Engineering and Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Central South University, Changsha 410083, China.
³ Department of Physics and Astronomy, Clemson Nanomaterials Institute, Clemson University, Clemson, SC 29634, USA.

Abstract

Large-scale low-cost synthesis methods for potassium ion battery (PIB) anodes with long cycle life and high capacity have remained challenging. Here, inspired by the structure of a biological cell, biomimetic carbon cells (BCCs) were synthesized and used as PIB anodes. The protruding carbon nanotubes across the BCC wall mimicked the ion-transporting channels present in the cell membrane, and enhanced the rate performance of PIBs. In addition, the robust carbon shell of the BCC could protect its overall structure, and the open space inside the BCC could accommodate the volume changes caused by K⁺ insertion, which greatly improved the stability of PIBs. For the first time, a stable solid electrolyte interphase layer is formed on the surface of amorphous carbon. Collectively, the unique structural characteristics of the BCCs resulted in PIBs that showed a high reversible capacity (302 mAh g^-1 at 100 mA g^-1 and 248 mAh g^-1 at 500 mA g^-1), excellent cycle stability (reversible capacity of 226 mAh g^-1 after 2100 cycles and a continuous running time of more than 15 months at a current density of 100 mA g^-1), and an excellent rate performance (160 mAh g^-1 at 1 A g^-1). This study represents a new strategy for boosting battery performance, and could pave the way for the next generation of battery-powered applications.

Keywords: bionic structures; potassium ion battery; rate performance; reversible capacity; term stability.