Supramolecular Self-Assembly of Methylated Rotaxanes for Solid Polymer Electrolyte Application

Li⁺-conducting solid polymer electrolytes (SPEs) obtained from supramolecular self-assembly of trimethylated cyclodextrin (TMCD), poly(ethylene oxide) (PEO), and lithium salt are investigated for application in lithium-metal batteries (LMBs) and lithium-ion batteries (LIBs). The considered electrolytes comprise nanochannels for fast lithium-ion transport formed by CD threaded on PEO chains. It is demonstrated that tailored modification of CD beneficially influences the structure and transport properties of solid polymer electrolytes, thereby enabling their application in LMBs. Molecular dynamics (MD) simulation and experimental data reveal that modification of CDs shifts the steady state between lithium ions inside and outside the channels, in this way improving the achievable ionic conductivity. Notably, the designed SPEs facilitated galvanostatic cycling in LMBs at fast charging and discharging rates for more than 200 cycles and high Coulombic efficiency.