An Ultrarobust Composite Gel Electrolyte Stabilizing Ion Deposition for Long‐Life Lithium Metal Batteries

Abstract

Lithium metal batteries (LMBs) possessing ultrahigh energy density are promising next-generation battery systems, but the short cycle life and safety concerns caused by the uncontrollable growth of lithium dendrites impede their broad applications. Herein, to address these issues, an ultrarobust composite gel electrolyte (CGE) that can effectively stabilize ion deposition for LMBs is designed via fabricating a specially structured aerogel as the matrix. The gel electrolyte matrix with a 3D interconnected highly porous structures and good affinity with liquid electrolytes is fabricated via compositing bacterial cellulose (BC) and Li 0.33 La 0.557 TiO 3 nanowires (LLTO NWs) into an aerogel. The composite aerogel matrix demonstrates excellent wettability and liquid electrolyte uptake (586 ± 5%), and the resulting CGE presents exceptional Young's modulus of 1.15 GPa and an extremely high lithium-ion transference number of 0.88. More significantly, the synergistic effect from the robust BC skeleton and LLTO NWs enabling stable ion deposition effectively suppresses the growth of lithium dendrites. Armed with the CGE, ultrastable symmetric Li/Li cells demonstrate a long cycle life of 1200 h and highly stable performance even at a high current density of 5 mA cm −2 . Furthermore, half cells with the CGE exhibit remarkable enhancement in capacity, cycling stability, and rate performance.

Deep‐Eutectic‐Solvent‐Based Self‐Healing Polymer Electrolyte for Safe and Long‐Life Lithium‐Metal Batteries

“…This result confirms that below al imiting current density,D SP electrolyte efficiently stabilizes the Li electrodeposition owing to its mesh size,w hich is much smaller than the nucleation points. [34] To further investigate the compatibility between the DSP electrolyte and Li metal anode,t he galvanostatic cycling of as ymmetric Li jjLi cell was assessed at 0.2 mA cm À2 .F or ac ell using the DES electrolyte (inset in Figure 3c), the voltage hysteresis increased sharply with the cycling time owing to the continuously thickening SEI (as verified by an increase in the interfacial resistance,E IS;s ee Figure S8). A Angewandte Chemie severe voltage drop appeared after 155 h, indicating as hort circuit caused by Li dendrite growth.…”

A Review of Functional Separators for Lithium Metal Battery Applications

“…With the same aim of enhancing mechanical properties and ionic conductivity simultaneously, Yang and co-workers synthesized composite electrolytes. They prepared a 3D interconnected porous structure and increased the affinity with liquid electrolytes via compositing bacterial cellulose (BC) and Li 0.33 La 0.557 TiO 3 nanowires (LLTO NWs) into the aerogel matrix [ 165 ] ( Figure 19 ). The affinity provided excellent wettability, and a composite gel electrolyte (CGE) exhibited a Young’s modulus of 1.15 GPa.…”

“…( a ) Schematic of the effect of ( b ) a commercial separator and ( c ) a BC/LLTO CGE on Li deposition in a battery. Reprinted with permission from [ 165 ]. Copyright (2019) WILEY-VCH.…”

An Overview of Bacterial Cellulose in Flexible Electrochemical Energy Storage

“…Ding and co-workers [121] reportedt he preparation of ah ighly robust free-standing BC/Li 3x La 2/3Àx TiO 3 nanowirec omposite (BC/LLTO) as the CGE forh igh-performancea nd reliable LMBs (Figure 16 a). As ab enign Li-containinga nd fast single ion conductor,L LTOi sc apable of promoting Li + transportation and improving the homogeneity of Li + fluxion.I na ddition, numerous and stable oxygen-containing groups on the surface of BC nanofibersa re conducive to the uniform deposition and nucleation of Li on the negative side (Figure 16 b).…”