A simple synthesis of highly ordered microporous carbon nanospheres for high performance potassium-ion batteries

Abstract Potassium-ion batteries (PIBs) are considered as a promising alternative to lithium-ion batteries (LIBs) for low cost and large-scale application. However, owing to the large size of K ions, traditional carbon materials still undergo poor rate performance, low capacity and unsatisfied cycling life. Herein, we design and synthesize highly ordered microporous carbon nanospheres (OMCNSs) for the first time through a very simple method. In PIBs, OMCNSs negative electrode deliver an ultrahigh capacity of 256.9 mA h g−1 at 0.5 A g−1 after 500 cycles, outstanding rate performance of 156.6 mA h g−1 at 5 A g−1 after 2000 cycles. Furthermore, when coupled with potassium Prussian blue positive electrode, the potassium-ion full cells also display outstanding electrochemical performance, highlighting the practicability of OMCNSs. The excellent electrochemical performance is ascribed to the highly ordered micropores, which increase the action of physical adsorption and trap K+ stably.