ABSTRACT Extreme fast charging is essential for lithium‐ion batteries but is hindered by sluggish interfacial transport kinetics and the consequent lithium plating. Polyanionic materials are widely utilized in anodes due to their contributions to mechanical stability and their role in Li + conduction. However, excessive negative charge density in polyanionic chains often induces Li + accumulation and dendrite growth due to the overlap of local electric fields. Guided by Manning's counterion condensation theory and theoretical calculations, this work proposes a charge density regulation by identifying chondroitin sulfate lithium (CSLi) as optimal polyanionic chains at the anode interface. CSLi features a moderate average adjacent charge distance and minimal binding energy, which accelerates interfacial Li + desolvation and establishes a fast Li + conduction pathway via an alternating dissociation–coordination mechanism. Consequently, the CSLi‐based fast‐charging anode paired with NCM622 cathodes achieves 81.4% capacity at 8 C (7.5 min) and 79.3% at 10 C (6 min). Full cells demonstrate superior cycling stability under extreme fast‐charging conditions, retaining 87.0% of capacity after 300 cycles at 10 C. This stability is maintained with practical high‐loading cathodes (19 mg cm −2 ), delivering 87.5% capacity retention after 300 cycles. This work establishes a fundamental design principle for polyanionic chains, offering a viable pathway toward fast‐charging lithium‐ion batteries.
Li et al. (Wed,) studied this question.