Effects of binder content on low-cost solvent-free electrodes made by dry-spraying manufacturing for lithium-ion batteries

The commercial coating way of lithium-ion batteries has generally used wet coating technology so far. However, N-Methyl-2-pyrrolidone (NMP) is a toxic and expensive organic solvent using in this wet electrode manufacturing process, which is not environmentally friendly and greatly increases the cost of batteries. Herein, the solvent-free electrodes are prepared by electrostatic spraying without any solvent for lithium-ion batteries. The effects of different binder content on the mechanical, morphology and electrochemical performance are explored for solvent-free electrodes. When the contents of binder added are too much or little, the aggregates of binder and conductive agent more easily present uneven distribution in the whole electrodes. Moreover, the differences between the solvent-free electrodes and conventional wet electrodes are systematically compared. Notably, the binder and conductive agent are uniformly distributed with a point contact mode in the solvent-free electrode, which is conducive to rapid ions transfer and robust structural integrity, leading to a better rate capabilities and cycle performance. This work provides some reference value and guiding significance for the subsequent preparation and research of solvent-free electrodes.