Lithiophilic Cu-Li_(2)O matrix on a Cu Collector to Stabilize Lithium Deposition for Lithium Metal Batteries

Lithium metal anode is the most ideal candidate for next-generation energy storage system.However,the uncontrolled dendrite growth,infinite volume expansion,and undesired side reactions lead to serious safety issues and hinder their potential application.Herein,a pre-lithiation strategy is proposed to construct a high-lithiophilic Cu-Li_(2)O matrix on commercial Cu foil.The in situ-generated Li_(2)O promises adequate nucleation sites and strengthens solid electrolyte interphase and lateral lithium deposition.Meanwhile,the existence of 3D matrix reduces the local current density.The synergy effect of Li_(2)O and Cu suppresses the growth of lithium dendrites.As a result,Cu-Li_(2)O matrix reveals an enhanced lithium plating/stripping behavior with Coulombic efficiency of 98.46%after 270 cycles.The symmetrical cell assembled by Li-plated electrodes displays a prolonged lifespan of 1400 h.The work demonstrates a scalable and effective approach for modified current collectors toward stable Li metal anode.

Enhanced cycle stability of aprotic Li-O_(2) batteries based on a self-defensed redox mediator

LiBr as a promising redox mediator(RM)has been applied in Li-O_(2)batteries to improve oxygen evolution reaction kinetics and reduce overpotentials.However,the redox shuttle of Br_(3)^-can induce the unexpected reactions and thus cause the degradation of LiBr and the corrosion of Li anode,resulting in the poor cyclability and the low round-trip efficiency.Herein,MgBr_(2)is firstly employed with dual functions for Li-O_(2)batteries,which can serve as a RM and a SEI film-forming agent.The Br^(–)is beneficial to facilitating the decomposition of Li_(2)O_(2)and thus decreasing the overpotential.Additionally,a uniform SEI film containing Mg and MgO generates on Li anode surface by the in-situ spontaneous reactions of Mg^(2+)and Li anode in an O_(2)environment,which can suppress the redox shuttle of Br_(3)^-and improve the interface stability of Li anode and electrolyte.Benefiting from these advantages,the cycle life of Li-O_(2)battery with MgBr_(2)electrolyte is significantly extended.

AgTFSI Pretreated Li Anode in LiI-Mediated Li-O_(2)Battery:Enabling Lithiophilic Solid Electrolyte Interphase Generation to Suppress the Redox Shuttling

Although lithium iodide(LiI)as a redox mediator(RM)can decrease the overpotential in Li-O_(2)batteries,the stability of the Li anode is still one critical issue due to the redox shuttling.Here,we firstly present a novel approach for generating Ag and LiTFSI enriched Li anode(designated as ALE@Li anode)via a spontaneous substitution between pure Li and bis(trifluoromethanesulfonyl)imide silver,in a LiI-participated Li-O_(2)cell.It can induce the generation of a lithiophilic solid electrolyte interphase(SEI)enriched with Ag,F,and N species(e.g.,Ag_(2)O,Li-Ag alloy,LiF,and Li_(3)N)during cell operation,which contributes to promoting the electrochemical performance through the shuttling inhibition.Compared to a cell with a bare Li anode,the one with as-prepared ALE@Li anode shows an enhanced cyclability,a considerable rate capability,and a good reversibility.In addition,a synchrotron X-ray computed tomography technique is employed to investigate the inhibition mechanism for shuttling effect by monitoring the morphological evolution on the cell interfaces.Therefore,this work highlights the deliberate design in the modified Li anode in an easy-to-operate and cost-effective way as well as providing guidance for the construction of artificial SEI layers to suppress the redox shuttling of RMs in Li-O_(2)batteries.

具有碳纳米管基底的硫化交联聚苯乙烯刷的制备及其锂载体性能

不可控的锂枝晶生长、严重的体积膨胀以及脆弱的固态电解质中间相(SEI)严重制约了锂金属电池(LMBs)的实际应用。在本研究中,我们成功设计合成了一类具有碳纳米管基底的硫化超交联聚苯乙烯刷(CNT-g-sxPS),并将其用作新型的三维锂金属载体。CNT-g-sxPS的层次化大孔、中孔和微孔能够促进锂离子的传输,缓解锂负极的体积变化,提供高比表面积以降低局部电流密度,从而实现快速且均匀的锂沉积/剥离。同时,孔骨架表面均匀分布的含硫基团可以与锂原位反应生成含Li2S的SEI,有利于构筑稳定的负极/电解液界面。此外,碳纳米管基底还能提供快速的电子传输路径。因此,利用CNT-g-sxPS负载的锂金属负极(CNT-g-sxPS@Cu/Li)组装的Li|Li对称电池在1 mA cm^(-2)、1 mAh cm^(-2)下可稳定循环超过500 h。当与磷酸铁锂正极(LFP)匹配时,利用CNT-g-sxPS@Cu/Li负极组装的全电池在1 C下循环600圈后仍然具有101 mAh g^(-1)的放电比容量,容量保持率为77%。