Enhanced Li‐Ion Accessibility in MXene Titanium Carbide by Steric Chloride Termination. Issue 9 (6th January 2017)

• Record Type: Journal Article
• Authors: Kajiyama, Satoshi; Szabova, Lucie; Iinuma, Hiroki; Sugahara, Akira; Gotoh, Kazuma; Sodeyama, Keitaro; Tateyama, Yoshitaka; Okubo, Masashi; Yamada, Atsuo
• Is Part Of: Advanced energy materials. Volume 7:Issue 9(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-01-06
• Subjects: hybrid capacitors -- intercalation -- MXene -- negative electrode -- pseudocapacitors; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.201601873
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract : Pseudocapacitance is a key charge storage mechanism to advanced electrochemical energy storage devices distinguished by the simultaneous achievement of high capacitance and a high charge/discharge rate by using surface redox chemistries. MXene, a family of layered compounds, is a pseudocapacitor‐like electrode material which exhibits charge storage through exceptionally fast ion accessibility to redox sites. Here, the authors demonstrate steric chloride termination in MXene Ti2 C Tx ( Tx : surface termination groups) to open the interlayer space between the individual 2D Ti2 C Tx units. The open interlayer space significantly enhances Li‐ion accessibility, leading to high gravimetric and volumetric capacitances (300 F g −1 and 130 F cm −3 ) with less diffusion limitation. A Li‐ion hybrid capacitor consisting of the Ti2 C Tx negative electrode and the LiNi1/3 Co1/3 Mn1/3 O2 positive electrode displays an unprecedented specific energy density of 160 W h kg −1 at 220 W kg −1 based on the total weight of positive and negative active materials. Abstract : Steric chloride termination in MXene Ti2 C Tx opens the 2D interlayer space, which provides more accessible sites for intercalated Li ions, leading to the high electrochemical performance in Li‐ion nonaqueous electrolyte with less diffusion limitation. The Li‐ion hybrid capacitor with the MXene negative electrode achieves both high power and energy densities.