Achieving Fast and Efficient K+ Intercalation on Ultrathin Graphene Electrodes Modified by a Li+ Based Solid-Electrolyte Interphase

• Published in: Journal of the American Chemical Society Vol. 140; no. 42; pp. 13599 - 13603
• Main Authors: Hui, Jingshu, Schorr, Noah B, Pakhira, Srimanta, Qu, Zihan, Mendoza-Cortes, Jose L, Rodríguez-López, Joaquín
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 24.10.2018
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.8b08907

Advancing beyond Li-ion batteries requires translating the beneficial characteristics of Li+ electrodes to attractive, yet incipient, candidates such as those based on K+ intercalation. Here, we use ultrathin few-layer graphene (FLG) electrodes as a model interface to show a dramatic enhancement of K+ intercalation performance through a simple conditioning of the solid-electrolyte interphase (SEI) in a Li+ containing electrolyte. Unlike the substantial plating occurring in K+ containing electrolytes, we found that a Li+ based SEI enabled efficient K+ intercalation with discrete staging-type phase transitions observed via cyclic voltammetry at scan rates up to 100 mVs–1 and confirmed as ion-intercalation processes through in situ Raman spectroscopy. The resulting interface yielded fast charge–discharge rates up to ∼360C (1C is fully discharge in 1 h) and remarkable long-term cycling stability at 10C for 1000 cycles. This SEI promoted the transport of K+ as verified via mass spectrometric depth profiling. This work introduces a convenient strategy for improving the performance of ion intercalation electrodes toward a practical K-ion battery and FLG electrodes as a powerful analytical platform for evaluating fundamental aspects of ion intercalation.