Self-Templated Metal Glycerolate-Derived Trimetallic Layered Double Hydroxides with Tunable Metal Cation Concentration for High-Performance Supercapacitors

Layered double hydroxides (LDHs) are promising materials for electrochemical energy storage devices. Nonetheless, their practical application in supercapacitors is restricted by low electrical conductivity, severe aggregation, and poor internal stability. Surface modification and composition engineering are key strategies to overcome these challenges. This study presents the synthesis of flower-like trimetallic manganese nickel cobalt-layered double hydroxide (MnNiCo-LDH), derived from metal glycerolate. The NiCo-bimetal glycerolate spheres serve as both templates and metal sources for Ni and Co in the MnNiCo-LDH synthesis. These glycerolate spheres are prepared using a solvothermal method with different mole ratios (1:1, 2:1, and 1:2), and the MnNiCo-LDH is synthesized via a magnetic stirring process. The concentration of Mn was systematically varied to evaluate its effect on the structural and electrochemical properties. Under optimal conditions, MnNiCo-LDH achieves a high specific capacitance of 871.2 F/g at 20 mV/s with a broad potential window of 0.65 V. An asymmetric supercapacitor (ASC) was assembled with MnNiCo-LDH as the positive electrode and graphene as the negative electrode. The fabricated ASC demonstrates a maximum energy density of 36.9 Wh/kg at a specific power of 473.4 W/kg and exceptional cycling stability with 95.2% retention after 10,000 cycles. These results highlight the potential for developing efficient multimaterial electrodes for advanced energy storage applications.