Breaking Ionic Stagnation Zones for Ultrafast Charging in Low-Concentration Lithium-Ion Batteries
Rui Cao, Haipeng You, Zhanxuan Zhang, Yun Ji, Xinyu Mai, Yihui Liu, Long Chen, Chunzhong LiAbstract
Low-concentration electrolytes (LCEs) offer significant cost benefits for lithium-ion batteries (LIBs), but struggle with fast-charging demands due to sluggish Li+ transport, high desolvation barriers, and unstable interphase chemistry. Herein, we leveraged low-ionophilic solvents to form a high ionic-conductivity LCE, which enables rapid intersolvation cluster hopping networks, thus overcoming ionic stagnation zones. Our formulated electrolyte delivers an ionic conductivity of 9.2 mS cm–1, accelerates Li+ desolvation, and promotes anion-derived inorganic-rich interphases. As a result, graphite anodes achieve a high reversible capacity of 306.4 mAh g–1 at 5 C (81.5% of its capacity at 0.3 C) and deliver 332.4 mAh g–1 at −20 °C, retaining 88.9% of its room-temperature capacity. In 1 Ah graphite||LiNi0.8Co0.1Mn0.1O2 (NMC811) pouch cells, this electrolyte supports 76.6% capacity at 5 C, 84.1% retention over 1000 cycles at 0.5 C, and 82.0% retention after 100 cycles at 3 C, demonstrating the practical promise of LCEs for fast-charging LIBs.