Superior Electrochemical Performance of a Ni–P/Si Negative Electrode for Li-ion Batteries in an Ionic Liquid Electrolyte

To achieve electrode performance with both high capacity and long cycle life, we investigated the effect of the anion structure in an ionic liquid electrolyte on the electrochemical performance of an annealed Ni–P/(etched Si) negative electrode for Li-ion batteries. The electrode maintained a discharge capacity of 1890 mA h g−1 after 250 cycles in bis(fluorosulfonyl)amide-based ionic liquid electrolyte, which was approximately three times higher than that in bis(trifluoromethanesulfonyl)amide-based electrolyte.