Stabilizing Lithium Metal Batteries by Synergistic Effect of High Ionic Transfer Separator and Lithium–Boron Composite Material Anode

Abstract

The development of lithium (Li) metal batteries (LMBs) has been limited by problems, such as severe dendrite growth, drastic interfacial reactions, and large volume change. Herein, an LMB (8AP@LiB) combining agraphene oxide-poly(ethylene oxide) (PEO) functionalized polypropylene separator (8AP) with a lithium−boron (LiB) anode is designed to overcome these problems. Raman results demonstrate that the PEO chain on 8AP can influence the Li + solvation structure in the electrolyte, resulting in Li + homogeneous diffusion and Li + deposition barrier reduction. 8AP exhibits good ionic conductivity (4.9 × 10 −4 S cm −1 ), a high Li + migration number (0.88), and a significant electrolyte uptake (293%). The 3D LiB skeleton can significantly reduce the anode volume changes and local current density during the charging/discharging process. Therefore, 8AP@LiB effectively regulates the Li + flux and promotes the uniform Li deposition without dendrites. The Li||Li symmetrical cells of 8AP@LiB exhibit a high electrochemical stability of up to 1000 h at 1 mA cm −2 and 5 mAh cm −2 . Importantly, the Li||LiFePO 4 full cells of 8AP@LiB achieve an impressive 2000 cycles at 2C, while maintaining a high-capacity retention of 86%. The synergistic effect of the functionalized separator and LiB anode might provide a direction for the development of high-performance LMBs.

Amorphous lithiophilic cobalt‐boride@rGO interlayer for dendrite‐free and highly stable lithium metal batteries

“…The ohmic resistance (R e ) and charge transfer resistance (R ct ) of CoB@rGO/PP cell measured by electrochemical impedance spectroscopy (EIS) are considerably lower than that of both CoB/ PP and PP cell as shown in Figure 2E, revealing the ability of CoB@rGO to enrich the charge transfer paths and improve the kinetics of Li þ ions transport. 37 The Li ion transference number (t Li þ ) of the CoB@rGO separator was calculated by comparing the constant-pressure polarization curves (Figure 2F) and EIS data before and after polarization (equivalent circuit diagram and detailed calculation methods in Supporting Information). The high value of t Li þ as 0.53 further indicates the powerful ability of the CoB@rGO separator for high Li þ selectivity and strong concentration polarization suppression (Table S1).…”

Highly crystalline covalent triazine frameworks modified separator for lithium metal batteries

“…Among the various coating materials, such as inorganic nanoparticles [13,17,18] and polymers with ionic groups [19][20][21] , covalent organic frameworks (COFs) are emerging porous materials with tunable nanoscale pores and tailorable skeletons. They usually contain light elements such as C, H, O, N, and B.…”

Co/Li2S of chemical confinement decorated electrochemically stable Co(OH)F nanoarrays enabling dendrite-free flexible 3D Li anodes

“…In addressing such intractable issues, many strategies have been developed, including electrolyte modification, 8,9 artificial solid–electrolyte interface construction, 10–12 separator modification 13–15 and 3D electrode fabrication. 16–18 According to the theory of “Sand's time,” the charge accumulation on some spots causes the local current density to exceed the limiting current density, which induces uncontrollable Li dendrite growth.…”