Sandwich network structure silicon/carbon anode material for lithium-ion batteries based on bacterial cellulose

Silicon(Si) is one of the anode materials to replace graphite electrodes due to large specific capacity. However, the volume expansion of silicon anode material and instability of solid electrolyte interphase (SEI) layer greatly limits their practical applications. Herein, we demonstrate a novel sandwich network structure silicon-carbon anode composites and explored as electrode material for lithium-ion batteries (LIBs). The CBC/Si/NC composites were synthesized by using bacterial cellulose (BC) as the structural template and retains the three-dimensional network structure of BC and has a high specific surface area which ease the volume expansion of silicon during the charge-discharge process. Meanwhile, silicon nanoparticles covered with dopamine, the outer carbon, uniformly attached to the cellulose surface. The internal and external carbon layers improve the conductivity of the composite and can accelerate the diffusion and electronic transmission of lithium ions. The sandwich network structure composite anode demonstrates excellent cycle stability and a high reversible specific capacity of 889mAh·g −1 after 200 cycles at a current density of 0.5 A·g −1 .