双电解液锂空气电池正极介观传质分析

Mesoscopic mass transfer analysis of positive electrode in dual-electrolyte lithium-air battery

基于Martini力场原理,使用粗粒化分子动力学模拟方法,研究双电解液锂空气电池正极中各粒子的介观传递规律。结果显示:H2O、Li+、OH-、O2粒子的扩散系数随温度的升高而增大;随着碳纳米管长度及碳纳米管的种类个数的增加而减小;溶液体系中同时存在长度为6与12 nm的碳纳米管时,溶液中各粒子的扩散系数随着6 nm碳纳米管含量的增加呈现先上升后下降的趋势,并在其比例为1∶1时达到最大值。研究发现:增大体系的孔隙率,调整体系的复杂度有利于溶液体系中各粒子的扩散系数提升,改善锂空气电池的整体性能。

Based on Martini force field principle, coarse-grained molecular dynamics simulation method was used to study the mesoscopic mass transfer law of positive electrode in the dual-electrolyte lithium-air battery. The study indicates that the diffusion coefficients of H2O, Li+, OH- and O2 beads are increased with the increase of temperature,the diffusion coefficients are decreased with the increase of length of carbon nanotubes and types of carbon nanotubes. The diffusion coefficient of the beads increases first and then decreases with the increase of the content of 6 nm carbon nanotubes, and reaches the maximum at the ratio of 1∶1. It is found that increasing the porosity of the system and adjusting the complexity of the system are conducive to improve diffusion coefficient of each bead in the solution system and performance of lithium-air battery.