Intercalation of Layered Materials from Bulk to 2D

• Published in: Advanced materials (Weinheim) Vol. 31; no. 27; pp. e1808213 - n/a
• Main Authors: Stark, Madeline S., Kuntz, Kaci L., Martens, Sean J., Warren, Scott C.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.07.2019
• Subjects: 2D intercalation; Charge transfer; Diffusion rate; Electronic devices; Electronic structure; Energy storage; Heterostructures; Intercalation; Layered materials; Materials science; Optical properties; Optoelectronic devices; optoelectronics; scaling relationships; Semiconductor devices; Storage batteries; Synthesis; Transistors; Two dimensional materials; scaling relationships; 2D intercalation; energy storage; optoelectronics
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201808213

Intercalation in few‐layer (2D) materials is a rapidly growing area of research to develop next‐generation energy‐storage and optoelectronic devices, including batteries, sensors, transistors, and electrically tunable displays. Identifying fundamental differences between intercalation in bulk and 2D materials will play a key role in developing functional devices. Herein, advances in few‐layer intercalation are addressed in the historical context of bulk intercalation. First, synthesis methods and structural properties are discussed, emphasizing electrochemical techniques, the mechanism of intercalation, and the formation of a solid‐electrolyte interphase. To address fundamental differences between bulk and 2D materials, scaling relationships describe how intercalation kinetics, structure, and electronic and optical properties depend on material thickness and lateral dimension. Here, diffusion rates, pseudocapacity, limits of staging, and electronic structure are compared for bulk and 2D materials. Next, the optoelectronic properties are summarized, focusing on charge transfer, conductivity, and electronic structure. For energy devices, opportunities also emerge to design van der Waals heterostructures with high capacities and excellent cycling performance. Initial studies of heterostructured electrodes are compared to state‐of‐the‐art battery materials. Finally, challenges and opportunities are presented for 2D materials in energy and optoelectronic applications, along with promising research directions in synthesis and characterization to engineer 2D materials for superior devices. Few‐layer (2D) intercalation compounds present an attractive pathway to tune the structure, as well as the electronic, optical, and energy‐storage properties near the atomic limit. Recent advances in 2D intercalation are summarized in the historical context of bulk intercalation as well as scaling relationships to motivate research in synthesizing and characterizing 2D materials for optoelectronic and energy‐storage devices.