Fabrication of Binder-Free Pencil-Trace Electrode for Lithium-Ion Battery: Simplicity and High Performance

A binder-free and solvent-free pencil-trace electrode with intercalated clay particles (mainly SiO₂) is prepared via a simple pencil-drawing process on grinded Cu substrate with rough surface and evaluated as an anode material for lithium-ion battery. The pencil-trace electrode exhibits a high reversible capacity of 672 mA h g^–1 at 100 mA g^–1 after 100 cycles, which can be attributed to the unique multilayered graphene particles with lateral size of few micrometers and the formation of Li_xSi alloys generated by interaction between Li⁺ and an active Si produced in the electrochemical reduction of nano-SiO₂ in the clay particles between the multilayered graphene particles. The multilayered graphene obtained by this process consists of 1 up to 20 and occasionally up to 50 sheets and thus can not only help accommodating the volume change and alleviating the structural strain during Li ion insertion and extraction but also allow rapid access of Li ions during charge–discharge cycling. Drawing with a pencil on grinded Cu substrate is not only very simple but also cost-effective and highly scalable, easily establishing graphitic circuitry through a solvent-free and binder-free approach.