Creating Lithium‐Ion Electrolytes with Biomimetic Ionic Channels in Metal–Organic Frameworks

Abstract

Solid-state electrolytes are the key to the development of lithium-based batteries with dramatically improved energy density and safety. Inspired by ionic channels in biological systems, a novel class of pseudo solid-state electrolytes with biomimetic ionic channels is reported herein. This is achieved by complexing the anions of an electrolyte to the open metal sites of metal-organic frameworks (MOFs), which transforms the MOF scaffolds into ionic-channel analogs with lithium-ion conduction and low activation energy. This work suggests the emergence of a new class of pseudo solid-state lithium-ion conducting electrolytes.

Recent Progress of Hybrid Solid‐State Electrolytes for Lithium Batteries

“…[63] As displayed in Figure 6c,t he structure of MIT-20 ((CH 3 ) 2 NH 2 )[Cu 2 Cl 3 BTDD]·(DMF) 4 (H 2 O) 4.5 )i sc omposed of alternate pair of Cu atoms connected either by BTDD 2À or by BTDD 2À and m 2 -Cl, which shows anionic framework balanced by free dimethylammonium (DMA). [64] As eries of MOF-basedH SSEs have been fabricatedb yc omplexing the anions (ClO 4 À )o fa lithium electrolyte (LiClO 4 in propylene carbonate) to the open metal sites (OMSs) of MOFs, which provides Li + transport channels alongt he pores,a ss hown in Figure6e. to yield anionic phase with al arge content of free metal cations residing in the pores.…”

Porous Core–Shell CuCo2S4 Nanospheres as Anode Material for Enhanced Lithium‐Ion Batteries

“…Electrochemical impedance spectroscopy (EIS) measurements were carried out to further investigate the electrochemical‐reaction kinetic properties of the core–shell CuCo 2 S 4 nanospheres (Figure f). The numerical diameter of the semicircle on the Z re axis in the high‐frequency region is related to the charge transfer resistance ( R ct ) and liquid resistance ( R e ) of the electrode . The Warburg impedance is associated with the diffusion of Li + ions into the CuCo 2 S 4 electrode, corresponding to the slope factor at low frequencies .…”

“…The numerical diameter of the semicircle on the Z re axis in the high-frequency region is related to the charge transfer resistance (R ct )a nd liquid resistance (R e )o f the electrode. [52,53] The Warburg impedance is associated with the diffusion of Li + ions into the CuCo 2 S 4 electrode, corresponding to the slope factor at low frequencies. [54,55] Ther esistance of the fresh CuCo 2 S 4 electrode was close to 23.4 W,w hich was smaller than that of the CoS and Cu 2 Se lectrodes (63.3 and 42.4 W,r espectively).…”

High Uptake and Fast Transportation of LiPF6 in a Porous Aromatic Framework for Solid‐State Li‐Ion Batteries

“…The voltage versus time profiles of the battery under each current density corresponding to the rate capacity test were shown in Figure e. The voltage profiles were very stable, and there was no obvious fluctuation under different current densities, indicating good circularity and stable interface of the battery . Figure f further compares the cycling performance LiFePO 4 ∥LiPF 6 @ PAF‐1∥Li cell and other SSLIBs that have been well studied. LiFePO 4 ∥LiPF 6 @PAF‐1∥Li cell exhibits high capacity with robust electrochemical stability and importantly, it sustained rigorous long‐term current density as high as 4C.…”

“…f) Cycling performance of Li/LiFePO 4 cells with other SSEs and LiPF 6 @PAF‐1 in long term cycles (first 100 cycles). (LLZO‐containing PCPSE, CPMEA‐LATP base PCPSE, Cathode‐supported PPAL, PEO 20 ‐LiTFSI‐MXene 0.02 , LPC@UM, PLLN …”