The Functions and Applications of Fluorinated Interface Engineering in Li‐Based Secondary Batteries

Abstract

Past few years have witnessed great progress in energy storage technology and material characterization methods, which stimulated the development of novel energy storage devices suitable for largescale industrial applications. [1][2][3][4] Among all the energy conversion avenues, electrochemical means have the advantages of environmental benignity, high transforming efficiency, and long lifespan, which are expected to overcome the intrinsic shortcomings of directly unavailable renewable energy sources such as wind power, tidal power, and solar energy, whose defects often lie in distribution inhomogeneity and space-time limitations across the world. [5] So, a large variety of electrochemical energy storage devices emerges as urgently demanded in reality during the past two centuries to meet different requirements in social production and residential lives. Particularly, secondary battery technology, also called rechargeable battery, is a reliable type of electrochemical system with ability to charge and discharge repeatedly taking advantage of reversible chemical reactions. [6,7] In contrast to primary battery first designed by Alessandro Volta in 1799, rechargeable battery systems such as nickel-metal hydride batteries, [8] nickel-cadmium batteries, [9] lead-acid batteries, [10] lithium-ion batteries (LIB), and polymer LIBs [11] have huge potential to apply in portable electronic devices, electric vehicles (EV), implantable medical equipments, and static smart power grid due to their distinct advantages of durability, energy density, and cost performance. Accordingly, many of these have achieved great success in market during the past few decades. Specially, LIB, served as a milestone in electrochemical energy storage technology history for humankind and first commercialized by Sony in 1991 with a configuration of cobalt oxide cathodes and graphite anodes, [12] has been widely deployed in 3C (Computer, Communication, Consumer electronics products) fields to revolutionize our modern life so far.As shown in Figure 1, the working mechanism of LIBs usually follows a typical "rocking chair" style, which is featured by the reversible charge-carrier (alkali metal ion) separation and recombination at the electrode/electrolyte interface in host materials including cathodes and anodes. [7] To be specific, when exerted

In situ interface engineering of highly nitrogen-rich triazine-based covalent organic frameworks for an ultra-stable, dendrite-free lithium-metal anode

“…37 The mainstream SEI design mainly focuses on in situ or ex situ coating layers, which relies on the high lithium affinity, high ionic conductivity, and continuously stable Li + migration. 38,39 However, it is difficult to form an effective electronic connection between the Li metal anode and the coating layers, resulting in sluggish interfacial charge transfer; 40 thus, manufacturing the artificial COF SEI film with an in situ strategy is imperative to achieve ultra-long stable, dendrite-free lithium metal anode. Therefore, it is significant but challenging to construct an artificial COF SEI layer with uniform Li + flux and deposition for hindering the direct contact of Li metal with the electrolyte, thereby fabricating an ultra-long stable, dendrite-free lithium metal anode.…”

Precise Control of Li+ Directed Transport via Electronegative Polymer Brushes on Polyolefin Separators for Dendrite‐Free Lithium Deposition

“…[15][16][17] It is known that well-designed conductive hosts with a large specific surface area can regulate ion distribution by reducing local current density. [7,18] Moreover, the lithophilic chemistry of polar groups such as CN, CO, and OH in the matrix could accelerate cation transport, [19][20][21] but the unstable structure may cause drastic capacity decay. In addition, high-concentration salt electrolyte and fluorinated solvents have also been adopted to modify the physicochemical properties of solid electrolyte interface (SEI) films.…”

Highly soluble organic nitrate additives for practical lithium metal batteries

“…16,17 The Li dendrites easily crack SEI, leading to the exposure of active Li and subsequent continuous reactions between Li and electrolytes. 18,19 As a result, the repeated Li dendrite growth, SEI fracture, and SEI reconfiguration induce rapid consumption of limited Li reservoir and lean electrolytes, finally failing Li metal batteries. [20][21][22] Therefore, constructing homogeneous SEI is of vital significance to promoting uniform Li deposition and achieving long-cycling Li metal batteries.…”

“…However, SEI is usually heterogeneous and thus induces nonuniform Li deposition (named Li dendrites) 16,17 . The Li dendrites easily crack SEI, leading to the exposure of active Li and subsequent continuous reactions between Li and electrolytes 18,19 . As a result, the repeated Li dendrite growth, SEI fracture, and SEI reconfiguration induce rapid consumption of limited Li reservoir and lean electrolytes, finally failing Li metal batteries 20–22 .…”