Entropy‐Driven Solvation toward Low‐Temperature Sodium‐Ion Batteries with Temperature‐Adaptive Feature

Abstract

Salt precipitation at temperatures far above the freezing point of solvents is primarily responsible for performance decay of rechargeable batteries at low temperature, yet is still challenged by a lack of in‐depth understanding of the design principle and ultimate solutions. Here, this is resolved via tuning the entropy of solvation in a strong‐solvation (SS) and weak‐solvation (WS) solvent mixture, in which a solvation structure can spontaneously transform at low temperature to avoid salt precipitation, endowing the electrolyte with a temperature‐adaptive feature. The results affirm that such temperature‐adaptive electrolyte ensures encouraging low‐temperature performance in a hard carbon||Na2/3Ni1/4Cu1/12Mn2/3O2 full cell with 90.6% capacity retention over 400 cycles at −40 °C. The generality of the concept is further expanded to construct a series of SS–WS electrolytes as potential candidates for rechargeable low‐temperature sodium‐ion batteries. The work shed lights on the importance of entropy tuning and affords a rational viewpoint on designing low‐temperature electrolytes.

Sustainable, low Ni-containing Mg-doped layered oxides as cathodes for sodium-ion batteries

“…The slowing of the electrochemical reactions often yields capacity loss and eventual cell failure. 62 The excellent electrochemical features found for F0N05 prompted us to test the cycling behavior at −15 °C (Fig. 10a).…”

Prussian White Cathode Materials for All-Climate Sodium-Ion Batteries

“…The solvation structure variations with (b) nonadaptive electrolyte and (c) temperature-adaptive electrolyte from room temperature to low temperature. Reprinted with permission from ref . Copyright 2023 Wiley-VCH.…”

“…Yet, at low temperature, ions or solvent molecules severely aggregate, , leading to an increased degree of order (or Δ S < 0) and the formation of a nonhomogeneous system, which seriously deteriorates the performance of the electrolyte (Figure b). Thus, we have proposed the design principle of a low-temperature electrolyte that avoids salt precipitation during (dis)­charging while preserving the high stability of the electrolyte to the electrodes . We consider that adjusting the salt solvation structure by introducing solvents with different solvation abilities can boost the solubility of the salt at low-temperature by reducing the system degree of order (Δ S > 0).…”

Electrolyte engineering and material modification for graphite‐based lithium‐ion batteries operated at low temperature

“…To further develop liquid electrolytes with fast Li + transport kinetics and enhanced interface stability, a relatively new electrolyte, high-entropy electrolyte (HEE), has entered our field of vision nowadays. [97][98][99][100] HEEs are generally composed of multiple cations and anions, typically five or more, which are mixed in equal F I G U R E 9 (A) Illustrations of the solution structures and the process of Li + -intercalation graphite layer in LCE and LHCE and the capacityvoltage curves of graphite|Li cells with different electrolytes at 0.1 C under −20°C. [93] Copyright 2021, Wiley-VCH.…”