Multiple conductive network for KTi2(PO4)3 anode based on MXene as a binder for high-performance potassium storage

Abstract

KTi2(PO4)3 is a promising anode material for potassium storage, but suffers from low conductivity and difficult balance between high capacity and good structural stability. Herein, the Ti3C2Tx MXene is used as a multifunctional binder to fabricate the KTi2(PO4)3 electrode by the traditional homogenizing-coating method. The MXene nanosheets, together with the conductive agent super P nanoparticles, construct a multiple conductive network for fast electron/ion transfer and high electrochemical kinetics. Moreover, the network ensures the structural stability of the KTi2(PO4)3 electrode during the de-intercalation/intercalation of 4 K+ ions, which is beneficial for simultaneously achieving high capacity and good cycle performance. Therefore, the MXene-bonded KTi2(PO4)3 electrode delivers a reversible capacity of 255.2 mAh/g at 50 mA/g, outstanding rate capability with 132.3 mAh/g at 2 A/g, and excellent cycle performance with 151.6 mAh/g at 1 A/g after 2000 cycles. This work not only suggests a high-performance anode material for potassium-ion batteries, but also demonstrates that the MXene is a promising binder material for constructing conductive electrodes in rechargeable batteries.