A Multifunctional Additive Capable of Electrolyte Stabilization and Structure/Interphases Regulation of High‐Energy Li‐Ion Batteries

High‐energy‐density lithium metal batteries (LMBs) hold enormous potential for future energy storage systems but are plagued by poor cycling stability and safety concerns, especially under high‐rate conditions. The addition of fluorinated solvents to the electrolyte is effective in enhancing the stability of the lithium metal anode (LMA) and improving safety for LMBs. However, the extensive introduction of fluorinated solvents is not conducive to the transport of lithium‐ions (Li+), thereby negatively affecting the rate performance of LMBs. Herein, a safe ether electrolyte (SEE) is designed that exhibits both high Li+ conductivity and nonflammability, while maintaining high compatibility with the LMA. Li–LiNi0.8Mn0.1Co0.1O2 (NMC811) cells utilizing SEE can demonstrate remarkable electrochemical performance, delivering a discharge capacity of 113.1 mAh g⁻¹ at rates as high as 30 C and maintaining 90% of their initial capacity over 300 cycles at 10 C. Moreover, a practical Li‐NCM811 full cell assembled with SEE achieves stable cycling at 3 C.

A Safe Ether Electrolyte Enabling High‐Rate Lithium Metal Batteries

Yang,

Li,

Zou

et al. 2024

Built‐In Trimodal Molecular Interaction Effect Enables Interface‐Compatible and Temperature‐Tolerance Aqueous Zinc Batteries

Chen,

Ouyang,

Wang

et al. 2024

Aqueous zinc‐ion batteries compatible with a wide temperature range and long cycle lifespan show great application prospects but are greatly limited by the unstable electrode‐electrolyte interfaces and mismatched electrolytes. This report presents the pathway of succinamic acid (SA) additive‐induced built‐in trimodal molecular interaction for constructing sustainable aqueous zinc batteries. As confirmed, such trimodal molecular interaction falls into the following patterns: the binding state of the H─F bond between SA and polyvinylidene fluoride (PVDF) binder, the micellar aggregation state in aqueous electrolyte, and the spontaneous adsorption state at Zn anode–electrolyte interface. Benefiting from the above synergistic effect, the Zn electrode shows a highly reversible deposition/stripping behavior over the wide temperature range (−10–50 °C) when paired with the optimized electrolyte. Specially, an impressive 3530 h‐cycle lifespan of the Zn symmetrical cell is achieved at the conditions of 1 mA cm−2 and 1 mAh cm−2. Beyond that, significantly improved storage capability and cycle performance are demonstrated in both aqueous Zn‐MnO2 and Zn‐I2 batteries. Given the good balance between the working temperature range, ionic conductivity, and Zn2+ transfer number of this trace molecule‐mediated electrolyte, this design paradigm provides new insights into developing advanced aqueous batteries, including but not limited to zinc‐based systems.

Leakage‐Free and Non‐Flammable High‐Safety Li Metal Battery Using 85.3 wt.% Multifunctional Organic Lithium Salt as Quasi‐Solid Electrolyte

Liu,

Qiao,

Lin

et al. 2024

Safety issues of lithium metal batteries caused by leakageable, inflammable, and unstable electrolytes and lithium dendrites are a major concern worldwide. Herein, an ultra‐concentrated electrolyte composed of 85.3 wt.% of a novel phosphate quaternary ammonium lithium salt (PQ‐3Li) in fluoroethylene carbonate is prepared, labeled as CPQE. CPQE reveals an exceptional ionic conductivity (0.32 × 10−3 S cm−1), a high lithium transference number (0.66), an electrochemical stability window above 6 V, and a superb fire resistance. Li|CPQE|Li cells show stable cycling performance without lithium dendrites for 1000 h, and a solid‐electrolyte‐interface layer with an inorganics‐rich inner layer and an organics‐rich outer layer is confirmed using computation simulation, electron probe microanalysis, and X‐ray photoelectron spectroscopy. Li|CPQE|NCM cells present a discharge capacity of 162 mAh g−1 at 0.1 C, and a Coulombic efficiency of up to 99%. A commercial LED bulb can be lighted up by the Li|CPQE|NCM cell for at least 1 h without performance deterioration while prolonging the cycling time. The fabricated CPQE‐based pouch cells own terrific safety and power supply capacity. No leakage, thermal runaway, combustion, or explosion behavior is detected during the nailing penetration test, implying large potential applications for developing the next generation of high‐safety lithium batteries.