z Energy Technology & Environmental Science La 2 Ti 2 O 7 As Nanometric Electrode Material: An Emerging Candidate For Supercapacitor Performance Amtul Nashim + , [a] Soumyashree Pany + , [a] K. M. Parida,* [a] and J. Nanda [b] In this study, first time the nanometric powder of La 2 Ti 2 O 7 (abbreviated as LTO) is taken as the electrode material for supercapacitor. The prepared material is characterized by various characterization techniques to know its structural and textural properties. The specific capacitance of the La 2 Ti 2 O 7 is calculated from charge discharge curve. The Nyquist plot, bode plot and the plot of real capacitance vs. imaginary capacitance is well in support of supercapacitive activity of La 2 Ti 2 O 7 . The La 2 Ti 2 O 7 exhibits 71 F/g of specific capacitance in 2 M KOH with 95.7% retention after 5000 cycles is due to the effective access of electrolyte to the redox sites owing to its layered structure. As these finding are new to the scientific community and demonstrate the great potential of La 2 Ti 2 O 7 as electrode material for supercapacitor, the current findings may give a new pave in the area of supercapacitor research. 1. Introduction For the past few decades, energy production from renewable resources is the main topic of concern. Beside this, its storage and production (when required) is drawing the attention of many researchers. Hence, supercapacitor will be considered as the promising energy storage device, in the forth coming years which would bridge the gap between conventional capacitor and batteries. In this regards, many research work has been devoted to develop electrode materials for supercapacitor application with high specific capacitance, fast charging discharging, high power and energy density with long cyclic life. [1] Usually, supercapacitor are classified into two types (a) EDLC (electric double layer capacitor) and (b) pseudocapacitor. An EDLC stores charges by reversible adsorption of ions, and where as the mechanism of storage of charge in a pseudocapa- citor is due to fast surface reversible redox reaction. [2] The use of transitional metal oxides like MnO 2 , NiO, V 2 O 5 , Co 3 O 4 , RuO 2 , TiO 2 , etc as electrodes have been increased in recent years owing to its high specific capacitance, high energy density and structural flexibility. [3] But there are some bottle neck like low conductivity, short cyclic stability, low energy and power density etc. which needs to be improved upon. The current research also focuses on ternary metal oxides like NiCo 2 O 4 , ZnCo 2 O 4 and Zn 2 SnO 4 , which is emerging as a promising and low cost pseudocapacitive material. As ternary metal oxides posses multiple oxidation states it shows higher supercapaci- tive activity than their corresponding binary systems. Here, in ternary system both the cations are responsible for the electrochemical energy storage. [4] Besides transitional metal oxides, the work on rare earth metal oxides is also attracting the researchers. C.D. Lokhande et al. prepared SSSD (symmetric solid state supercapacitor device) with La 2 O 3 thin film. Further they also studied the porous honey comb like La 2 O 3 doped graphitic porous carbon and MnO 2 /La 2 O 3 microsphere for supercapacitor activity. [5] Eu 2 O 3 ,Y 2 O 3 , Nb 2 O 5 , CeO 2 etc. are few examples of other rare earth metal oxides which are used as a electrode material for the supercapacitor either in the native form or with composite with some other materials. [6] X. U. Feng et al used rare earth metal in their work on colloidal supercapacitor. [7] To the best of our knowledge, hardly any report is there on ternary based rare earth systems for supercapacitor activity. La 2 Sn 1.6 Zr 0.4 O 7 nanocrystalline pyro- chlore shows 74 F/g of specific capacitance at 1 mA/cm 2 as calculated from charge-discharge curve. [8] Co 2 P 2 O 7 , Mn 2 P 2 O 7 and Ni 2 P 2 O 7 are few transitional metal based polyphosphates which are considered as the interesting electrode materials for supercapacitor performance. [9] Mn-doped Rb 2 Ru 1.5 Mn 0.5 O 7-δ , La 2 Sn 2 O 7-δ , La 2 Zr 2 O 7-δ etc. are the examples of active pyrochlore materials for oxygen reduction reaction. [10] Recently, Lithium Lanthanum Titanates is used as an additive for the enhancement of the performance of Lithium ion batteries. [11] Nanometric La 2 Ti 2 O 7 powder is considered as the novel negative electrode materials for Ni/oxide rechargeable batteries. [12] Currently, many researches have been carried out on battery-type electrode materials which have high redox behaviour and used for supercapacitor applications. [13] The battery behaviour of La 2 Ti 2 O 7 is known but the performance of La 2 Ti 2 O 7 as active electrode material for supercapacitor applica- tion is not known to the scientific community. [a] Dr. A. Nashim, + Dr. S. Pany, + K. M. Parida Centre for Nano Science and Nano Technology, Institute of Technical Education and Research, Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, 751030, India E-mail: kulamaniparida@soauniversity.ac.in amtulnokt@gmail.com soumya.pany84@gmail.com [b] Prof. J. Nanda Department of Physics, Institute of Technical Education and Research, Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, 751030, India E-mail: jyotirmayeenanda@soauniversity.ac.in [ + ] Authors have equal contribution Supporting information for this article is available on the WWW under https://doi.org/10.1002/slct.201903227 Full Papers DOI: 10.1002/slct.201903227 12037 ChemistrySelect 2019, 4,12037–12042 © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim