Asymmetric Solvents Regulated Crystallization-Limited Electrolytes for All-Climate Lithium Metal Batteries

Electrolytes that can keep liquid state are one of the most important physical metrics to ensure the ions transfer with stable operation of rechargeable lithium-based batteries at a wide temperature window. It is generally accepted that strong polar solvents with high melting points favor the safe operation of batteries above room temperatures but are susceptible to crystallization at low temperatures (≤−40 °C). Here, a crystallization limitation strategy was proposed to handle this issue. We demonstrate that, although the high melting points of ethylene sulfite (ES, −17 °C) and fluoroethylene carbonate (FEC, ≈23 °C), their mixtures can avoid crystallization at low temperatures, which can be attributed to low intermolecular interactions and altered molecular motion dynamics. A suitable ES/FEC ratio (10 % FEC) can balance the bulk and interface transport of ions, enabling LiNi_0.8Mn_0.1Co_0.1O₂||lithium (NCM811||Li) full cells to deliver excellent temperature resilience and cycling stability over a wide temperature range from −50 °C to +70 °C. More than 66 % of the capacity retention was achieved at −50 °C compared to room temperature. The NCM811||Li pouch cells exhibit high cycling stability under realistic conditions (electrolyte weight to cathode capacity ratio (E/C)≤3.5 g Ah⁻¹, negative to positive electrode capacity ratio (N/P)≤1.09) at different temperatures.     

Unlocking the Interfacial Adsorption-Intercalation Pseudocapacitive Storage Limit to Enabling All-Climate,High Energy/Power Density and Durable Zn-Ion Batteries

Sluggish storage kinetics and insufficient performance are the major challenges that restrict the transition metal dichalcogenides (TMDs) applied for zinc ion storage, especially at the extreme temperature conditions. Herein, a multiscale interface structure-integrated modulation concept was presented, to unlock the omnidirectional storage kinetics-enhanced porous VSe_2−x⋅n H₂O host. Theory research indicated that the co-modulation of H₂O intercalation and selenium vacancy enables enhancing the interfacial zinc ion capture ability and decreasing the zinc ion diffusion barrier. Moreover, an interfacial adsorption-intercalation pseudocapacitive storage mechanism was uncovered. Such cathode displayed remarkable storage performance at the wide temperature range (−40–60 °C) in aqueous and solid electrolytes. In particular, it can retain a high specific capacity of 173 mAh g⁻¹ after 5000 cycles at 10 A g⁻¹, as well as a high energy density of 290 Wh kg⁻¹ and a power density of 15.8 kW kg⁻¹ at room temperature. Unexpectedly, a remarkably energy density of 465 Wh kg⁻¹ and power density of 21.26 kW kg⁻¹ at 60 °C also can be achieved, as well as 258 Wh kg⁻¹ and 10.8 kW kg⁻¹ at −20 °C. This work realizes a conceptual breakthrough for extending the interfacial storage limit of layered TMDs to construct all-climate high-performance Zn-ion batteries.