Hydrothermal Synthesis and Symmetrical Supercapacitor Study of 1D Ln‐H2PDA (Ln=La and Sm) Metal‐Organic Frameworks

Rare earth based metal‐organic frameworks (RE‐MOFs) are gaining importance in energy storage applications. Herein, we report the synthesis of two new RE‐MOFs (Ln‐H2PDA, Ln=La and Sm) under hydrothermal conditions using pyridine‐2,6‐dicarboxylic acid (H2PDA) linker. The single‐crystal analysis revealed that La‐H2PDA MOF crystallizes into monoclinic system with P 21/c space group. Sm‐H2PDA MOF also has the same crystal system, which is confirmed by powder X‐ray diffraction pattern. These MOFs are evaluated for their charge storage behaviour using conventional 3‐electrode system. Both La‐H2PDA and Sm‐H2PDA delivered high specific capacity of 220 C g−1 (488 F g−1) and 711 C g−1 (1580 F g−1) at a current density of 1 A g−1, respectively. Furthermore, a symmetric Swagelok device (Sm‐H2PDA∥Sm‐H2PDA) has been fabricated using Sm‐H2PDA MOF as working electrodes. The maximum energy density and power density delivered by this device are 18 Wh kg−1 and 3744 W kg−1. New Sm and La‐based based 1D‐MOFs are synthesized using water as a solvent in a Pyrex tube immersed in an oil bath at 100 °C. MOF sythesis is carried out using H2PDA ligand under mild hydrothermal conditions. Among the two Ln‐MOFs, Sm‐H2PDA shows higher charge storage capacity (1580 F g−1) in a 3‐elecrode sytem and delivers power density of 3744 W kg−1 from the fabicated symmetric supercapacitor device, Sm-H2PDASm-H2PDA .