A Dynamic, Electrolyte-Blocking, and Single-Ion-Conductive Network for Stable Lithium-Metal Anodes

Abstract

Implementation of lithium (Li)-metal anodes requires developments to solve the heterogeneity and instability issues of naturally formed solid-electrolyte interphase (SEI). The artificial SEI, as an alternative, enables an ideal interface by regulating critical features such as fast ion transport, conformal protection, and parasitic reaction mitigation. Herein, for the first time, we integrate all of these desired properties into a single matrix, the dynamic single-ion-conductive network (DSN), as a multifunctional artificial SEI. The DSN incorporates the tetrahedral Al(OR) 4 À (R = soft fluorinated linker) centers as both dynamic bonding motifs and counter anions, endowing it with flowability and Li + single-ion conductivity. Simultaneously, the fluorinated linkers provide chain mobility and electrolyte-blocking capability. A solution-processed DSN coating was found to simultaneously hinder electrolyte penetration, mitigate side reactions between Li and electrolyte, maintain low interfacial impedance, and allow homogenous Li deposition. With this coating, long cycle life and high Coulombic efficiency are achieved for Li-metal battery in a commercial carbonate electrolyte.

All‐Solid‐State Lithium–Organic Batteries Comprising Single‐Ion Polymer Nanoparticle Electrolytes

“…A comparison of the conductivity‐storage modulus plots of our single‐ion NP electrolytes with reported values for representative single‐ion electrolytes (Figure ) demonstrates the significant advances of this study in the area of solid‐state electrolytes . Notably, although our single‐ion NP electrolytes are all‐organic, they show superior mechanical properties and improved Li + ion transport properties in comparison to their organic–inorganic counterparts (Figure , shaded in green) . Hereafter, to evaluate battery performance, we focus on the single‐ion NP electrolyte comprising 50 wt % of 20 nm NPs, owing to its optimal properties, as described above.…”

“…Furthermore, in the case of salt‐doped PEO‐based electrolytes, the lithium transference number ( t ) is typically as low as 0.3, resulting in considerable cell polarization at high current densities . Single‐ion conducting polymer electrolytes may resolve these problems, but their conductivities are orders of magnitude lower than those of conventional dual‐ion conducting polymer electrolytes …”

Design of a Multifunctional Interlayer for NASCION‐Based Solid‐State Li Metal Batteries

“…Liquid electrolytes also have a limited electrochemical window and are often incompatible with the use of metallic Li as anode. [ 2,3 ] In SSLBs the liquid electrolyte is entirely replaced by a solid electrolyte enabling safe operation even under abuse conditions as well as compatibility with high‐voltage cathodes (electrochemical stability window up to 6.0 V can be achieved [ 4 ] ) and high‐capacity Li metal anode paves the way for dramatically gravimetric and volumetric energy densities for the full cells. [ 5,6 ] In addition, SSLBs are expected to have prolonged cycle life because of the suppressed chemical “cross talk” between electrodes.…”

Cover Feature: All‐Solid‐State Lithium–Organic Batteries Comprising Single‐Ion Polymer Nanoparticle Electrolytes (ChemSusChem 9/2020)

“…Ac omparison of the conductivity-storage modulus plotso f our single-ion NP electrolytes with reported values for representatives ingle-ion electrolytes (Figure 4) demonstratest he significant advances of this study in the area of solid-state electrolytes. [41][42][43][44][45][46] Notably,a lthough our single-ion NP electrolytes are all-organic, they shows uperior mechanical properties and improved Li + ion transport properties in comparison to their organic-inorganic counterparts (Figure 4, shadedi n green). [43,53,54] Hereafter,t oe valuateb attery performance, we focus on the single-ion NP electrolyte comprising 50 wt %o f 20 nm NPs, owing to its optimal properties, as described above.…”

“…[38] Single-ion conductingp olymer electrolytes may resolve these problems, but their conductivities are orders of magnitude lower than those of conventional dual-ion conducting polymere lectrolytes. [39][40][41][42][43][44][45][46] Undoubtedly,t he development of an ew solid-state electrolyte that has high conductivity and ah igh t Li þ value would lead to radicala dvances in lithium-organic battery technologies. Unfortunately,t his topic has not received much attentiona nd examples of high-performance all-solid-state lithium-organic batteries that exhibit mechanicals tability, ah igh specific capacity,a nd good rate capability are extremely challenging.…”