Exploration of Advanced Electrode Materials for Approaching High‐Performance Nickel‐Based Superbatteries

Abstract

The surging interest in high performance, low‐cost, and safe energy storage devices has spurred tremendous research efforts in the development of advanced electrode active materials. Herein, the in situ growth of zinc–iron layered double hydroxide (Zn–Fe LDH) on graphene aerogel (GA) substrates through a facile, one‐pot hydrothermal method is reported. The strong interaction and efficient electronic coupling between LDH and graphene substantially improve interfacial charge transport properties of the resulting nanocomposite and provide more available redox active sites for faradaic reactions. An LDH–GA||Ni(OH)2 device is also fabricated that results in greatly enhanced specific capacity (187 mAh g−1 at 0.1 A g−1), outstanding specific energy (147 Wh kg−1), excellent specific power (16.7 kW kg−1), along with 88% capacity retention after >10 000 cycles. This approach is further extended to Ni–MH and Ni–Cd batteries to demonstrate the feasibility of compositing with graphene for boosting the energy storage performance of other well‐known Ni‐based batteries. In contrast to conventional Ni‐based batteries, the nearly flat voltage plateau followed by a sloping potential profile of the integrated supercapacitor–battery enables it to be discharged down to 0 V without being damaged. These findings provide new prospects for the design of high‐performance and affordable superbatteries based on earth‐abundant elements.

In Situ Growth of Ni–Zn–Fe Layered Double Hydroxide on Graphene Aerogel: An Advanced Two‐in‐One Material for Both the Anode and Cathode of Supercapacitors

“…Thus, the mesoporous and uniform structure of the LDH-GA nanocomposite provides rapid ion transport pathways, leading to an effectively expedited kinetics of the electrode reactions to attain enhanced supercapacitive performances. [17] Moreover, from the BJH pore size distribution analysis (Figure 3d), the estimated pore width of the GA is %3.5 nm. The BJH curve of the LDH-GA nanocomposite depicts a sharp peak at %3.6 nm along with a broader peak centered at %10 nm.…”

“…[16] Moreover, compositing the materials with graphene helps to tailor the distance between individual graphene nanosheets, prevents restacking, and provides additional spaces for easy accessibility of the electrolyte ions. [17] In light of the earlier considerations, in this work, we report for the first time the in situ growth of the Ni-Zn-Fe LDH nanoparticles within the 3D graphene aerogel (GA) framework through a simple one-step hydrothermal method. In this LDH-GA nanocomposite, the LDH nanoparticles present great redox properties, and the 3D GA affords facile and fast electron/ ion transport.…”

“…The TEM image of the LDH-GA nanocomposite clearly shows that the LDH nanoflakes are uniformly distributed on the graphene nanosheets, implying a strong interaction between the LDH nanoflakes and the graphene sheets. [17,19] The energy-dispersive X-ray spectroscopy (EDS) spectrum of the LDH-GA nanocomposite displays elemental peaks for Ni, Zn, Fe, C, O, and N elements (Figure S2, Supporting Information). Elemental mapping of the LDH-GA nanocomposite demonstrates the homogenous distributions of Ni, Zn, and Fe elements as the principal elemental components of the LDH sample, as well as the C, N, and O elements across the entire matrix (Figure 2j).…”

“…The sharper diffraction peaks of the LDH-GA nanocomposite indicate the good crystallinity of the as-prepared LDH-GA nanocomposite compared with the pure LDH sample. [17] We also studied the thermal stability and degradation behavior of the GO, GA, LDH, and LDH-GA samples in an air atmosphere at a heating rate of 10 C min À1 . Figure 3b shows the thermogravimetric analysis (TGA) curves of the samples.…”

“…It is also ascribed to the combustion of the more reactive functional groups including the carboxyl and epoxy functionalities (Figure 3b, green). [17,24] The second stage of weight loss at %550 C is attributed to the decomposition of more thermally stable carbonyls and hydroxyls groups. [25] The difference in the weight loss of the GA and GO after 600 C is attributed to the formation of the thermally stable rhombohedral graphite.…”