摘要
Quasi-solid polymer electrolytes(QSPEs)have been attracted significant attentions due to their benefits for simultaneously improved safety and energy density of batteries.Developing electrolytes capable of forming a stable solid electrolyte interphase(SEI)layer is a great challenge for QSPE-based lithium(Li)metal batteries(LMBs).Herein,unlike previously reports that the reconstruction of Li^(+)solvation structures in QSPE requires time-consuming bottom-up polymer synthesis,in current study,a facile approach has been developed to reconstruct the Li^(+)solvation structures in QSPE by adjustment of the salt concentrations.The high proportion of Li^(+)-anion complexes can effectively accelerate interfacial Li^(+)diffusion,mitigate the decompositions of organic solvents and induce the formation of a LiF-rich SEI layer,contributing to suppressed Li-dendrite growth.As a result,the Li/QSPE-3/LiFePO_(4)(LFP)cell performs an ultralong lifespan with capacity retention of 77.4%over 3000 cycles at 1 C.With a high-voltage LiCoO_(2)cathode,the cell can stably cycle over 200 cycles at 25℃(capacity retention of∼83.8%).With accelerated ion transport dynamics due to the reconstructed Li^(+)solvation structure,the QSPE-3(the salt concentration is 3 M)is applicable in a wide temperature range.The Li/QSPE-3/LFP full cell exhibits 58.1%and 102.6%of discharge capacity at−15 and 90℃,respectively,compared to those operated at 25℃This study demonstrates a facile yet effective approach on enhancing electrode/electrolyte interfacial stability,enabling the LMBs with simultaneously enhanced safety and high energy density.
基金
supported by the Natural Science Foundation of China(22379073,52373275)
the Natural Science Foundation of Tianjin,China(18JCZDJC31400)
the Ministry of Education Innovation Team(IRT13022).
