Electrostatic Regulation of Na+ Coordination Chemistry for High-Performance All-Solid-State Sodium Batteries
Penghui Song, Suli Chen, Junhong Guo, Junchen Wu, Qiongqiong Lu, Haijiao Xie, Qingsong Wang, Tianxi Liu
Abstract
Abstract Ion migration capability and interfacial chemistry of solid polymer electrolytes (SPEs) in all-solid-state sodium metal batteries (ASSMBs) are closely related to the Na + coordination environment. Herein, an electrostatic engineering strategy is proposed to regulate the Na + coordinated structure by employing a fluorinated metal–organic framework as an electron-rich model. Theoretical and experimental results revealed that the abundant electron-rich F sites can accelerate the disassociation of Na-salt through electrostatic attraction to release free Na + , while forcing anions into a Na + coordination structure though electrostatic repulsion to weaken the Na + coordination with polymer, thus promoting rapid Na + transport. The optimized anion-rich weak solvation structure fosters a stable inorganic-dominated solid–electrolyte interphase, significantly enhancing the interfacial stability toward Na anode. Consequently, the Na/Na symmetric cell delivered stable Na plating/stripping over 2500 h at 0.1 mA cm −2 . Impressively, the assembled ASSMBs demonstrated stable performance of over 2000 cycles even under high rate of 2 C with capacity retention nearly 100%, surpassing most reported ASSMBs using various solid-state electrolytes. This work provides a new avenue for regulating the Na + coordination structure of SPEs by exploration of electrostatic effect engineering to achieve high-performance all-solid-state alkali metal batteries. Graphical Abstract