Binder-free lithium ion battery electrodes made of silicon and pyrolized lignin

The synthesis, characterization, and performance of a binder-free negative electrode for a lithium-ion battery, consisting of renewable biopolymer lignin and silicon nanoparticles, are reported. By mixing, coating, and subsequent pyrolization, we fabricated uniformly inter-connected core-shell composite films of Si/C directly on the current collector, allowing for the assembly of coin-cells without the need of binder and conductive carbon. An excellent electrochemical performance was observed with a high specific capacity of 1557 mA h g(-1) and a stable rate performance from 0.18 A g(-1) to 1.44 A g(-1). Moreover, the Si-pLig electrode can be reversibly cycled at 0.54 A g(-1) with 89.3% capacity retention over 100 cycles. We also unveil a beneficial effect of 0.5% polyethylene oxide (PEO) on the morphology and electrochemical behavior of the Si/C composite electrodes.