High-loading and high-performance NiMn layered double hydroxide nanosheets supported on nickel foam for supercapacitor via sodium dodecyl sulfonate intercalation

Layered double hydroxide (LDH) supported on a conductive substrate is an effective way to obtain better capacitance performances. Unfortunately, acquiring high capacitance performances and high loading electrodes at the same time is challenging. Here, NiMn-LDH is supported on nickel foam by a one-step hydrothermal method using sodium dodecyl sulfonate (SDS) as an intercalator and soft template, achieving both high loadings and high capacitance performances. The electrode added 4 mmol SDS acquires the highest loading of 4.9 mg cm−2, highest area capacitances of 6311 mF cm−2 at 5 mA cm−2, and highest rate performance (52%). The hybrid supercapacitor assembled by the electrode exhibits the highest energy density of 34.61 Wh kg−1 under the power density of 831 W kg−1, and capacitances retention of 129% after 5000 cycles under 4 A g−1, and capacitances retention of 85% after 10,000 cycles under 10 A g−1. By adding SDS, LDH sheets grow to large sizes in thickness, length, and height and arrange densely together, causing the high loading. Meanwhile, the interlayer spacing above 2.5 nm by dodecyl sulfonates radical intercalation and the gaps sized of tens to hundreds of nanometers between nanosheets are favorable for electrolyte ion transport and increase in active materials utilization rate.