Single‐Molecule Additive Integrating Na‐Ion Reservoir, Cosolvent, and Diluent Functions for Low‐Temperature Na‐Ion Batteries
Abstract
ABSTRACT Na‐ion batteries hold great promise for low‐temperature energy storage, but their performance is severely constrained by Na‐ion loss, electrolyte freezing, and elevated viscosity. While each issue demands carefully tailored additive molecules, their combined use often leads to performance interference and complicates the manufacturing process. To overcome these concurrent challenges, we report an organic molecule, NaB(C 2 H 5 ) 4 , designed via machine learning, which incorporates three functional components in a single entity: Na + to replenish sodium inventory, B(C 2 H 5 ) 3 as a low‐freezing‐point cosolvent, and C 4 H 10 as a viscosity‐reducing diluent. NaB(C 2 H 5 ) 4 undergoes complete decomposition below 4.0 V via a free‐radical cleavage pathway, as confirmed by NMR and mass spectrometry. The incorporation of this molecule reduces the freezing point of the ether electrolyte to −85.0°C, and when formulated in an ether‐based electrolyte at −60°C, it achieves an ionic conductivity of 0.61 mS cm −1 and a viscosity of 49.7 mPa s. As a result, the hard carbon||P2‐Na 2/3 Ni 1/3 Fe 1/3 Mn 1/3 O 2 pouch cell exhibits an improved initial Coulombic efficiency from 64.8% to 83.7%, along with 90.2% capacity retention over 200 cycles at −60°C.
Article Details
Authors (13)
Shengfei Wang
State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Institute of Fiber Materials and Devices, Research Center of AI for Polymer Science, Collaborative Innovation Center of Chemistry for Energy Materials
Guanbin Wu
Chihao Zhao
State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular Science Institute of Fiber Materials and Devices Research Center of AI For Polymer Science Collaborative Innovation Center of Chemistry for Energy Materials Fudan University Shanghai China
Yanlong Zhao
Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering
Huajing Li
State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Institute of Fiber Materials and Devices, Research Center of AI for Polymer Science, Collaborative Innovation Center of Chemistry for Energy Materials
Ziyang Kang
State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Institute of Fiber Materials and Devices, Research Center of AI for Polymer Science, Collaborative Innovation Center of Chemistry for Energy Materials
Jiayong Du
State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular Science Institute of Fiber Materials and Devices Research Center of AI For Polymer Science Collaborative Innovation Center of Chemistry for Energy Materials Fudan University Shanghai China
Zhengyuan Tang
State Key Laboratory of Molecular Engineering of Polymers Department of Macromolecular Science Institute of Fiber Materials and Devices Research Center of AI For Polymer Science Collaborative Innovation Center of Chemistry for Energy Materials Fudan University Shanghai China
Zilong Zheng
Xinwei Du
State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Institute of Fiber Materials and Devices, Research Center of AI for Polymer Science, Collaborative Innovation Center of Chemistry for Energy Materials
Wenwen Wang
Xiaotian Guo
Yue Gao