储能科学与技术2025，Vol.14Issue(12)：4460-4469,10.DOI:10.19799/j.cnki.2095-4239.2025.0639
盐包水电解质浓度对固液界面影响规律
Concentration effects of water-in-salt electrolytes on electrode-electrolyte interfaces
摘要
Abstract
Water-in-salt(WIS)electrolytes are promising materials for developing high-performance electrochemical energy storage devices owing to their remarkable capability to broaden the electrochemical stability window,and a comprehensive understanding of their microscopic structures at the electrode-electrolyte interface and their response to concentration variations is critical for optimizing device performance.In this study,molecular dynamics simulations were employed to construct a graphene electrode-lithium bis(trifluoromethanesulfonyl)imide(LiTFS)electrolyte-interface model,which enabled the systematic investigation of the microscopic structural characteristics of the WIS electrolyte at the interface under varying concentration conditions.The results revealed the formation of an adsorbed layer(thickness:0.5 nm)on the electrode surface in the electrolyte(a LiTFSI aqueous solution).The distributions of ions and water molecules within this layer were significantly affected by the concentration,facilitating complex structural reorganization at the interface.Subsequent analysis of the Li+solvation structure identified 5 mol/kg as the critical concentration at which it underwent drastic changes.Beyond this threshold,the system entered the"WIS"state,which was characterized by a desolvation phenomenon.Additionally,the distribution of TFSI-changed significantly with the increasing electrolyte concentration,transitioning from a perpendicular orientation relative to the electrode surface to a parallel alignment.Concurrently,the interfacial ions and solvent molecules transitioned from a uniform distribution to a more tightly packed state.Moreover,the increased electrolyte concentration significantly disrupted the hydrogen bonding network among water molecules,further exacerbating the interfacial structural reorganization.These findings provide new theoretical insights into the concentration-dependent behavior of WIS electrolytes and their interactions with electrode interfaces,offering valuable perspectives for optimizing WIS electrolytes in electrochemical energy storage devices.关键词
锂电池/超级电容器/水系电解质/盐包水/固液界面/分子动力学模拟Key words
lithium-ion batteries/supercapacitors/aqueous electrolytes/solid-liquid interface/molecular dynamic simulation分类
信息技术与安全科学引用本文复制引用
YANG Lei,LIANG Chenglin,HE Haoyu,LI Xuzhe,MO Tangming..盐包水电解质浓度对固液界面影响规律[J].储能科学与技术,2025,14(12):4460-4469,10.基金项目
国家自然科学基金(52406226) （52406226）
广西壮族自治区自然科学基金(2025GXNSFBA089396) （2025GXNSFBA089396）
广西基地与人才专项(AD23026174) （AD23026174）
广西青年科技人才托举工程(GXYESS2025036) （GXYESS2025036）
广西石化资源加工及过程强化技术重点实验室开放基金(2024K009). （2024K009）
