Constructing novel deep eutectic composites based on hydrogen bond network as anode material for lithium-ion batteries

Abstract

The replacement of metallic materials with non-metallic materials as anode electrodes for lithium-ion batteries (LIBs) is an increasing hot spot for constructing a new generation of energy storage field. Here, a novel deep eutectic composites material consisting of quaternary ammonium salts (QASs) and N-methyl pyrrolidone (NMP) on the basis of hydrogen bonding reaction is used as the anode material of LIBs, boasting numerous advantages, including facile synthesis, environmental friendliness, superb conductivity, self-healing property, and multiple active sites to provide capacity. Typically, tetraethylammonium chloride (TEACl)/NMP delivered a reversible specific capacity of 764.8 mAh/g at 100 mA/g after cycling 420 times and coulombic efficiency is maintained near 100 % after 1000 cycles at 100 mA/g. The availability of hydrogen bonding network reduces the lattice energy of its components and creates defects, which is more favorable for the intercalation reaction in LIBs. Concurrently, the effect of hydrogen bonding reaction and the natural mobility of the deep eutectic composites exhibit high self-healing properties, facilitating the repair of the reaction interface in real time. An abundance of active sites that can bind Li+ to form LiH is used to provide capacity, which is also confirmed by density functional theory (DFT) method.