K6Nb10·8O30/C hybrid with multi-groove columnars prepared by molten-salt-assisted method as high-performances lithium ion anode

One-dimensional (1D) K6Nb10·8O30/C hybrid (KNO/C) with multi-groove columnars was synthesized through an efficient molten-salt-assisted method, in which the raw coal was served as the carbon source to enhance the conductivity of K6Nb10·8O30. Benefitting from the open transmission channels of K6Nb10·8O30 and the compact structure of KNO/C, the hybrid exhibits superior performances as anodes of lithium ion batteries (LIBs), including a specific capacity of 177.6/105.9 mA h g−1 at 400/800 mA g−1 after 800 cycles, a rate capability of 65.9 mA h g−1 at 2000 mA g−1 and long period cycling life (136.4 mA h g−1 at 1000 mA g−1 after 1200 cycles). Meanwhile, the capacitive-dominated process also contributes to the fast lithium ion storage. Consequently, simplified preparation process, clean raw materials, and outstanding performances enable the KNO/C hybrid to be a competitive anode. •KNO/C was prepared by molten-salt route with untreated coal as carbon precursor.•KNO/C hybrids present the multi-groove columnars morphologies with thin edges.•The hybrids exhibit outstanding electrochemical performances.•Open transport path and compact structure contribute to the well-performed hybrids.