Molten Salt Synthesis of Na‐Mn‐O Composites as Electrode Materials for High‐Performance Supercapacitors

Abstract

Manganese (Mn) based oxide materials are regarded as one of the favorable electrode materials, exhibiting a high energy density, low-cost and environmental benignity. In this work, we focus on synthesizing hollandite NaÀ MnÀ O composites as potential supercapacitor electrode materials by a facile molten salt technique. The structure and the morphology of the NaÀ MnÀ O system were significantly influenced by the synthesis temperature. The NaÀ MnÀ O composite synthesized at 550°C (NaÀ MnÀ O 550) demonstrates a distinct structure and a mixed morphology of nanorods and nanoparticles. The NaÀ MnÀ O 550 composite exhibits the best electrochemical performance with 306.0 F/g at 0.5 A/g and maintains 80.7 % capacity after 3000 charge-discharge times at 5 A/g. The largest specific capacitance of 64.0 F/g (0.3 A/g) and high energy density of 20.0 Wh/ kg (226.1 W/kg) were achieved in the assembled asymmetric supercapacitor device based on the NaÀ MnÀ O 550 and active carbon. Moreover, a long-cycling lifetime with 92.9 % retention after 10000 cycles was performed, which holds broad prospect for practical application in high performance energy storage devices.[a] Prof.

Hierarchically Porous Carbon Nanosheets from One-Step Carbonization of Zinc Gluconate for High-Performance Supercapacitors

“…Furthermore, the device maintains an energy density of 70.93 Wh kg −1 even at an ultrahigh power density of 47 kW kg −1 . As shown in Table S3 , the assembled devices exhibit excellent energy storage performance in both aqueous and organic electrolytes, and compare favorably with published supercapacitor work, with performance far exceeding devices such as WC-E-100-48//WC-E-100-48 (11.0 Wh Kg −1 , 26.3 W Kg −1 ) [ 41 ], WBMs-800//WBMs-800 (9.4 Wh Kg −1 , 227 W Kg −1 ) [ 42 ], Co(OH) 2 @CW//CW (6.5 Wh Kg −1 , 236 W Kg −1 ) [ 43 ], NiCo-P//CW (12.1 Wh Kg −1 , 395 W Kg −1 ) [ 44 ], N-M-O//Carbon (20.1 Wh Kg −1 , 226 W Kg −1 ) [ 45 ], and MnOx/PANI//Carbon (30.7 Wh Kg −1 , 800 W Kg −1 ) [ 46 ]. This means that the device has good application prospects.…”