Dendrite-free Li Anode Enabled by a Metal–Organic Framework-Modified Solid Polymer Electrolyte for High-Performance Lithium Metal Batteries

Abstract

Uncontrollable dendrite formation following the uneven deposition of lithium significantly affects the safety and service life of lithium metal batteries (LMBs). Therefore, a metal− organic framework solid polymer electrolyte (MSPE) with immobilized anions was prepared by the copolymerization of diallyl dicarbonate and a modified metal−organic framework material (MOFs). This not only avoids the agglomeration phenomenon caused by direct physical introduction of MOFs but also fixes the anion (TFSI − ) by the numerous coordinated unsaturated cation sites exposed on the MSPE. Based on space charge theory, anion coordination is an effective lithium dendrite elimination method that results in protection of the lithium anode within LMBs. As a result, the assembled Li/LiFePO 4 (LFP) cell exhibits a discharge specific capacity of 154.6 mA h g −1 and a capacity retention rate of 95.75% after 200 charge−discharge cycles at 0.2 C (1 C = 180 mA h g −1 ) at room temperature. More importantly, the assembled Li/Li symmetric cell with an MSPE exhibits a stable and low-potential cycle for 300 h at a current density of 0.5 mA cm −2 and achieves dendrite-free lithium deposition. This study provides a promising MOF-based solid polymer electrolyte for safe and high-performance LMBs.

Advances of Electroactive Metal–Organic Frameworks

“…[ 387 ] The resultant MOF‐modified solid polymer electrolyte improved ionic conductivity by five‐fold in contrast to the one without functionalized MOF. Similar strategy was applied to polymerization of diallyl dicarbonate [ 385 ] by substitution of poly(ethylene glycol) [ 387 ] using the same Zr MOF (UiO‐66‐NH 2 ). Meanwhile, a Zn MOF (ZIF‐8)/PEO modified commercial polyimide film followed by in situ polymerization of poly(ethylene glycol) diacrylate (PEGDA) and butyl methacrylate (BMA) in the presence of carbonate electrolyte, LiPF 6 in mixed ethylene carbonate (EC)/dimethylcarbonate (DMC)/ethylmethylcarbonate (EMC), to form asymmetric polymer electrolyte (Figure 14f).…”

“…Integration of MOFs and lithium salts as lithium-ion conducting electrolytes. The resultant electrolytes are applied as quasi-solid [377][378][379][380][381][382] or solid electrolytes, [75,101,[383][384][385][386][387][388][389][390][391] or solid electrolyte interphase (SEI) layer. [392][393][394][395][396] For instance, a Zr MOF (UiO-67) constructed by 4,4'-Biphenyldicarboxylic acid, L13, and ZrCl 4 was soaked with electrolyte of LiClO 4 in propylene carbonate to apply as quasi-solid electrolyte after integration of PTFE.…”

Metal organic framework optimized hybrid solid polymer electrolytes with a high lithium-ion transference number and excellent electrochemical stability

“…25 Shruti Suriyakumar et al and Sung-Jin Kang et al employed aluminum terephthalic acid metal organic framework (Al-TPA-MOF)-laden composite polymer electrolytes for all-solid-state lithium-metal batteries, which provided a considerable ionic conductivity of about 0.1 mS cm À1 at 60 C. 26,27 Wenyan Shang et al prepared a MOF-based SPEs using an in situ polymerization method to prevent the agglomeration of nanoparticles and alleviate the formation of lithium dendrites. 28 Qingxuan Shi et al designed multifunctional quasi-solid-state electrolytes composed of a conductive polymer and triazine-based MOF complexes, showing ideal ionic conductivity and superior rate performance. 29 The combination of MOFs and a polymer as solid electrolytes has been proved to be feasible in all-solid-state batteries.…”

“…26,27 Wenyan Shang et al prepared a MOF-based SPEs using an in situ polymerization method to prevent the agglomeration of nanoparticles and alleviate the formation of lithium dendrites. 28 Qingxuan Shi et al designed multifunctional quasi-solid-state electrolytes composed of a conductive polymer and triazine-based MOF complexes, showing ideal ionic conductivity and superior rate performance. 29 The combination of MOFs and a polymer as solid electrolytes has been proved to be feasible in all-solid-state batteries.…”

Regulated Li Electrodeposition Behavior through Mesoporous Silica Thin Film in Anode-Free Lithium Metal Batteries

“…These predicaments include the formation of Li dendrite and dead Li during the repeated Li cycling and high reactivity of Li metal as well as the manufacturing difficulties . The lack of control for the electrodeposition process and rough Li surface impedes the development of Li metal batteries. , A variety of approaches including the artificial layer on the Li metal, , separator modification, − electrolyte, − and nanostructured substrate have been used to restrain the formation of Li dendrite and to improve the interfacial stability of Li metal during cycling. , Recently, a porous material with a thin layer of lithiophilic coating was used as the scaffold for Li encapsulation as the lithiophilic composite has excellent wettability with liquefied Li . Tuning the lithiophobicity of the substrate could provide a stable electrode/electrolyte interface during cycling .…”