Negatively Charged Laponite Sheets Enhanced Solid Polymer Electrolytes for Long-Cycling Lithium-Metal Batteries

Abstract

Solid polymer electrolytes suffer from the low ionic conductivity and poor capability of suppressing lithium dendrites, which have greatly hindered the practical application of solid-state lithium-metal batteries. Here, we report a novel laponite sheet (LS) with a large negatively charged surface as an additive in a solid composite electrolyte (poly(ethylene oxide)-LS) to rearrange the lithium-ion environment and enhance the mechanical strength of the electrolytes (PEO-LS). The strong electrostatic regulation of laponite sheets assists the dissociation of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and constructs multiple transport channels for free lithium ions, achieving a high ionic conductivity of 1.1 × 10 −3 S cm −1 at 60 °C. Furthermore, LS facilitates the in situ formation of a LiFrich interface because of the boosting TFSI − anion concentration, which significantly suppresses lithium dendrites and prevents short circuit. As a result, the assembled LiFePO 4 |PEO-LS|Li battery demonstrates a long cycle life of over 800 cycles and a high Coulombic efficiency of 99.9% at 1C and 60 °C. When paired with a high-voltage NCM811 cathode, the battery also demonstrates excellent cycling stability and rate capability.

Laponite-Supported Gel Polymer Electrolyte with Multiple Lithium-Ion Transport Channels for Stable Lithium Metal Batteries

“…Furthermore, the negatively charged surface of laponite exerts an electrostatic adjustment effect, facilitating lithium salt dissociation and promoting the release of free Li + . At the same time, the oxygen-active sites on the laponite surface establish a Li + conductive path Figure a illustrates the temperature-dependent behavior of GPEs’ ionic conductivity from 20 to 80 °C, and Figure b displays the EIS plot at 30 °C.…”

“…40 At the same time, the oxygen-active sites on the laponite surface establish a Li + conductive path. 41 Figure 3a illustrates the temperature-dependent behavior of GPEs' ionic conductivity from 20 to 80 °C, and Figure 3b displays the EIS plot at 30 °C. The ionic conductivity of GPEs at 30 °C based on LAP and LAP@PDOL is 3.56 × 10 −4 and 5.16 × 10 −4 S cm −1 , respectively, which is significantly higher than that of the GPE based on the PP separator (7.75 × 10 −5 S cm −1 ).…”

“…17 3d−f shows that the t Li+ values of LAP@PDOL GPE, LAP GPE, and PP GPE are 0.40, 0.34, and 0.26, respectively. The higher t Li+ of LAP@PDOL GPE can be attributed to the immobilization of anions by the strong electrostatic modulation of laponite, 41 which can reduce the concentration polarization and improve the battery performance.…”

LLZTO Nanoparticle- and Cellulose Mesh-Coreinforced Flexible Composite Electrolyte for Stable Li Metal Batteries

“…Recently, an in situ method that directly converts liquid precursor solution to solid-state phase has gradually come into view and is considered a desirable way to overcome these obstacles mentioned above. , Second, although many efforts have been made, their ionic conductivity and transference number are still not satisfactory, which greatly limits the charge/discharge performance of batteries at high current density. Inspired by gel polymer electrolytes, introducing highly ion-conductive liquid components can enhance ionic conductivity greatly. , But the incorporated liquid would further degrade the mechanical properties of polymer electrolytes. , It is well proved that the introduced inorganic particles are able to compensate for the sacrificed mechanical properties and simultaneously improve the Li + transference number by Lewis acid–base interactions between ceramics and mobile anions. − …”

“…33,34 But the incorporated liquid would further degrade the mechanical properties of polymer electrolytes. 35,36 It is well proved that the introduced inorganic particles are able to compensate for the sacrificed mechanical properties and simultaneously improve the Li + transference number by Lewis acid−base interactions between ceramics and mobile anions. 37−39 In this work, an in situ thermal polymerization method was adopted to prepare the LZEC composite electrolyte, which contains gel polymer electrolyte, cellulose mesh, and LLZTO nanoparticles.…”