Rational design of microstructure and interphase enables highcapacity and long-life carbon anodes for potassium ion batteries

Disordered carbon is considered as a potential anode material for potassium ion batteries (PIBs) due to its advantages in rate capability compared to graphite. Nevertheless, its capacity is usually limited below 300 mAh g(-1). Herein, we demonstrate the performance of low-cost pitch derived carbon could be significantly boosted through synergistic microstructure design and electrode/electrolyte interphase regulation. A considerable amount of mesopore is produced to provide the extra active sites for K ion storage and meanwhile, facilitate the charge transfer. The optimized carbon anode delivers a remarkable capacity of 460 mAh g(-1) with outstanding rate capability up to 4.0 A g(-1). In-situ Raman spectra reveal the superb performance originates from K ion storage in both the mesopore and disordered graphene layers. The construction of a robust solid electrolyte interphase in ethylene glycol diethyl ether derived electrolyte further improves the long-term stability, leading to an exceptional capacity retention of 80% after 2000 cycles under a current density of 1.0 A g(-1). This strategy provides a facile approach to enhance the performance of carbon materials for PIBs via structure and interphase design. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study demonstrates that the performance of low-cost pitch derived carbon for potassium ion batteries can be significantly boosted through synergistic microstructure design and electrode/electrolyte interphase regulation. The optimized carbon anode delivers remarkable capacity and outstanding rate capability by providing extra active sites through the production of mesopores. Furthermore, the construction of a robust solid electrolyte interphase improves long-term stability and leads to exceptional capacity retention after cycles.