From wood pulp fibers to tubular SiO₂/C composite as anode for Li-ion battery: in-situ regulation of cellulose microfibrils by alkali solution

The microfibrils of wood pulp fibers in plant cell wall with an intrinsically regular and interlaced arrangement offer a stable porous structure. They could also provide outstanding mechanical strength and promote conductivity for Si-based materials. Upon these benefits, a method using wood pulp fibers to fabricate SiO₂/C composite is proposed. In this work, the alkali pretreatment interfering hydrogen bonds in wood pulp fibers in situ results in an enlarged spatial distance among cellulose microfibrils, exposing more free-surface. This empowered homogenously inlaid SiO₂ distribution along the carbon skeleton in the subsequent carbonization process. A highly mesoporous and the tubular morphology was achieved in the fabricated SiO₂/C composite. Furthermore, a high initial coulombic efficiency of 84.9 % and reversible specific capacity of 1130 mA h g⁻¹ with a coulombic efficiency of 98.8 % after 200 cycles at a current density of 0.1 A g⁻¹ was obtained.