Polymeric single lithium (Li)-ion conductors (SICs), along with inorganic conducting materials such as sulfides and oxides, have received significant attention as promising solid-state electrolytes. Yet their practical applications have been plagued predominantly by sluggish ion transport. Here, a new class of quasi-solid-state SICs based on anion-rectifying semi-interpenetrating polymer networks (semi-IPNs) with reticulated ion nanochannels are demonstrated. This semi-IPN SIC (denoted as sSIC) features a bicontinuous and nanophase-separated linear cationic polyurethane (cPU), which supports single-ion conducting nanochannels, and ultraviolet-crosslinked triacrylate polymer, which serves as a mechanical framework. The cPU phase is preferentially swollen with a liquid electrolyte and subsequently allows anionrectifying capability and nanofluidic transport via surface charge, which enable fast Li + migration through ion nanochannels. Such facile Li + conduction is further enhanced by tuning ion-pair (i.e., freely movable anions and cations tethered to the cPU chains) interaction. Notably, the resulting sSIC provides high Li + conductivity that exceeds those of commercial carbonate liquid electrolytes. This unusual single-ion conduction behavior of the sSIC suppresses anion-triggered interfacial side reactions with Li-metal anodes and facilitates electrochemical reaction kinetics at electrodes, eventually improving rate performance and cycling retention of Li-metal cells (comprising LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathodes and Li-metal anodes) compared to those based on carbonate liquid electrolytes.
Nonflammable lithium‐ion batteries (LIBs) are developed by adapting polymer solid electrolytes, but their insufficient electrochemical performance has not been fully addressed to date. Crosslinked polymer gel electrolytes with minimal organic solvents (hard gels) are proven to be nonflammable electrolytes, but their lithium metal battery performance is not comparable to those of conventional liquid electrolyte‐based systems. Here, a semi‐interpenetrating polymer network (semi‐IPN) ion‐transporting solid film that comprises a UV‐curable crosslinked polymer and tailored linear pyrrolidinium‐polyethylene glycol copolyester ion channels (named PNPEG), is reported. PNPEG can solvate Li+ effectively with the help of carbonate solvents. Molecular dynamics (MD) simulations confirm that Li+ transportation is accelerated due to the weaker interaction between PNPEG and Li+ ions than between the solvents and ions. The semi‐IPN electrolyte with PNPEG exhibits a flexible, nonflammable nature with an ionic conductivity of 4.2 × 10−1 mS cm−1 and Li+ transference number of 0.51. The individual pyrrolidinium‐Bis(trifluoromethanesulfonyl)imide (pyrrolidinium‐Tf2N) monomer and PEG chain ratios in PNPEG strongly affect battery performance, and the optimized semi‐IPN‐based lithium metal half cells with LiCoO2 cathodes show greatly improved discharge capacity retention at high c‐rate conditions owing to effective Li+ transportation and excellent cycling performance (93.8% capacity retention after 200 cycles at 0.5 C).
A novel organic ionic material, hole transport material‐1 (HTM‐I), was synthesized and characterized as a hole transport material for perovskite solar cells (PSCs), with the aim of replacing 2,2',7,7'‐Tetrakis[N,N‐di(4‐methoxyphenyl)amino]‐9,9'‐spirobifluorene (Spiro‐OMeTAD). HTM‐I was designed to incorporate both phenoxazine and benzimidazolium iodide salt structures, and its chemical structure was confirmed using 1H NMR and high‐resolution mass spectrometry. Differential scanning calorimetry measurements revealed that HTM‐I maintained an amorphous phase throughout the temperature range of −60 – 200 °C, and thermogravimetric analysis showed good thermal stability up to 220 °C. To evaluate its potential as a hole transport layer, perovskite solar cells were fabricated using a fluorine‐doped tin oxide (FTO)/compact‐TiO2/(Cs/FA/MA)Pb(I/Br)3/hole transport layer/Au configuration. The resulting n–i–p planar structure exhibited a power conversion efficiency of 10.4%.
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