Three-dimensional bacterial cellulose and MOF-74 derivatives as anode for high performance potassium-ion batteries

In this paper, we synthesized a three-dimensional hierarchical structure through simple hydrothermal combining pyrolysis method, which mainly encapsulated 0D Fe3N and Fe2O3 nanoparticles in 1D carbon nanotubes, which could be evenly grafted onto 2D bacterial cellulose (BC) carbon matrix, denoted as PBC@Fe2O3/Fe3N-CNT. As an anode material, the composite showed excellent electrochemical performance both in potassium ion battery (PIBs) and sodium ion battery (SIBs). Specifically, after 200 cycles at a current density of 100 mA g−1, it showed discharge capacity of 342.2 mAh g−1 and 420.6 mAh g−1 in PIBs and SIBs, respectively. The excellent performance is mainly due to the particularity of the hierarchical structure. The hierarchical limitation of the low dimensional structure to the high dimensional structure can effectively buffer the volume expansion caused by the ion deinterleaving process, and PBC is conducive to the structural stability of the material. In addition, the "tip growth method" successfully achieved the in-situ growth of N-doped carbon nanotubes (CNT), which not only avoids the agglomeration of nanoparticles to a certain extent, but also improves the conductivity of the material and promotes ion transport. This work provides ideas for exploring other carbon-based composites to realize high-performance metal ion batteries.