Synthesis of alkali and acid-mediated rGO–metakaolin nano composites for supercapacitor application

Revathi, T.; Janani, Krishnamachari; Jeyalakshmi, R.

doi:10.1007/s10854-021-07211-8

Cited by 3 publications

(9 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The mix requires a slightly elevated temperature of about 60–80 °C for hardening because of its low reactivity at ambient conditions. For practical applications, an optimal quantity of calcium‐containing source of GGBS (15–30 % partial replacement) has been used to harden the matrix at room temperature [58–59] . According to the literature, the blend of slag in fly ash (10–30 %) activated by water glass with a SS/SH ratio in the range 1.5–2.5 and 10–12 M of NaOH give workable mixes in an optimum setting time with a compressive strength of 30–55 MPa (28 days).…”

Section: Resultsmentioning

confidence: 99%

“…For practical applications, an optimal quantity of calcium-containing source of GGBS (15-30 % partial replacement) has been used to harden the matrix at room temperature. [58][59] According to the literature, the blend of slag in fly ash (10-30 %) activated by water glass with a SS/SH ratio in the range 1.5-2.5 and 10-12 M of NaOH give workable mixes in an optimum setting time with a compressive strength of 30-55 MPa (28 days). However, concurrent geopolymerisation reactions involved in various stages tend to take place at a higher rate in the alkali silicatemediated geopolymerisation reaction that produced cohesive fresh mixes.…”

Section: Setting Time and Workability Of The Matrixmentioning

confidence: 99%

“…In this respect, the effect of NS addition on microstructural changes has been taken for investigation in our early work and the reaction mechanism was studied by employing in‐situ ATR FT‐IR spectroscopy and found to have positive influence on reactivity of the binder. [58] . The effect of the addition of MPC, a superplasticiser and in conjunction with Nano silica at different dosages evaluated to promote the hydration of the calcium compound in GGBS by controlling the rapid release of Aluminium in silica‐rich phases during the first stage of dissolution reaction.…”

Section: Introductionmentioning

confidence: 99%

“…In this study, an understanding of the behaviour of calcium even at a low level of 20 % of GGBS and determining the effects of nano-silica on the final reaction products are central to the application of this composite. In this respect, the effect of NS addition on microstructural changes has been taken for investigation in our early work and the reaction mechanism was studied by employing in-situ ATR FT-IR spectroscopy and found to have positive influence on reactivity of the binder.. [58] The effect of the addition of MPC, a superplasticiser and in conjunction with Nano silica at different dosages evaluated to promote the hydration of the calcium compound in GGBS by controlling the rapid release of Aluminium in silica-rich phases during the first stage of dissolution reaction. While fresh properties were evaluated through setting time, workability tests and the mechanical performance of hardened matrix were assessed by compressive strength tests.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Influence on Rheology and Microstructure of Nanosilica and Modified Polycarboxylate in Water‐Glass‐Activated Fly Ash/Ground Granulated Blast Furnace Slag Geopolymers

2023

Self Cite

View full text Add to dashboard Cite

This study establishes the effect of nano silica (NS) in the alkali activator on the behaviour of rheology and microstructure of Alkali activated material. The rheological behaviour of the Fly ash (FA)‐Ground granulated blast furnace slag (GGBS) (4 : 1) activated using water glass of Ms 1.1 (SiO2/Na2O), with nano silica (NS), Modified Poly carboxylate (MPC) was studied and the link between the composition and fundamental behaviour are reported. A total of 12 mortar mixtures were cast by varying the dose of NS from 0–3 %, and MPC 0–2.5 % and their fresh properties were obtained from the slump, setting time and flow value. The compressive strengths of mortars showed an increasing trend from 40 to 55 MPa with NS addition from 0–2.5 wt% at an optimal dose of 1 % MPC. The suspensions with and without NS fit well with Herschel‐Bulkley model, in the hysteresis cycle. The incorporation of NS at a threshold value below 2 % leads to a drastic change in viscosity with increasing time at a constant shear rate, implying. a thixotropy with yield‐type behaviour that are associated with the rebuilding of the flocculated structure with time. The nucleating effect of NS progressively improved the strength of the mix, due to the formation of compact gel microstructure which was confirmed by SEM micrograph with fewer pores. NS improves CSH gel and gelatinous silica phase in the matrix as is evident from the formation of the SiQ4 structural unit as it is absent in control. The poly (Sialate) structural unit in geopolymer ascertained from 29Si, 27Al MAS NMR chemical shift corresponds to Alq3(3Si) with the absence of remnant Al(IV) peak of Fly ash in NS (2.%) activated samples.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Setting Time and Workability Of The Matrixmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Influence on Rheology and Microstructure of Nanosilica and Modified Polycarboxylate in Water‐Glass‐Activated Fly Ash/Ground Granulated Blast Furnace Slag Geopolymers

2023

Self Cite

View full text Add to dashboard Cite

show abstract

“…Metakaolin hardened by Revathi et al using phosphoric acid and alkali, was reinforced with reduced graphene oxide to fabricate supercapacitor nanocomposite electrode. 102 The specific capacitances of the electrodes are: 53.2 and 42.5 F/g. The electrochemical stability of the electrode, proved that graphene and graphene-based nanomaterials have enormous potential to tailor organic and inorganic materials for energy storage applications.…”

Section: Nanomaterials Batteries and Supercapacitorsmentioning

confidence: 99%

Progress towards sustainable energy storage: A concise review

Folorunso

Olukanmi

Shongwe

2023

Engineering Reports

View full text Add to dashboard Cite

In this study, the benefits and challenges of existing energy storage systems are presented. The environmental threats and the apparent unreliability of fossil fuel energy sources necessitate the need for alternative sources of electrical power. Energy storage has been sourced from mechanical, electrical, thermal, chemical, and electrochemical systems. Perhaps, an electrochemical energy storage system, is a better option toward achieving a net zero carbon‐dioxide emission by 2050. Energy storage sources, such as: batteries and supercapacitors, can be reliably fabricated from the hybrid of polymers and two‐dimensional materials for electric vehicles, aviation, and grid load balancing applications. The performances of lithium‐ion batteries are yet to meet the requirements for high‐duty machines and devices. Graphite, the anode of lithium‐ion batteries, suffers from low capacity and high volume‐expansion, resulting in cracking and fracture of the electrodes. Herein, based on evidence from literature, this study suggests substituting graphite with polymer nanocomposite or metal‐oxide nanocomposites such as: conducting polymers, copper oxide, and graphene. This approach, giving attention to these materials' excellent electrochemical, thermal, electrical, mechanical, and redox properties, offers possible ways to overcome the limited limitations confronting lithium‐ion battery technology.

show abstract

Acid Activation in Low-Carbon Binders: A Systematic Literature Review

Park,

Pimenta,

Bezerra

2023

Buildings

View full text Add to dashboard Cite

Geopolymers have emerged as an alternative binding material to Ordinary Portland Cement (OPC). Recently, there has been an increase in studies exploring the synthesis of these materials using acid activation rather than traditional alkaline activation. This approach offers benefits such as good strength at an early age, better thermal properties, and a chemical activator that emits less carbon to be produced. In addition, it provides resistance to efflorescence and leaching, which are common challenges associated with alkali-activated products. This work analyzed the scientific advances in acid activation in synthesizing an alternative binder to OPC. To this end, a systematic review of the last five years of scientific literature was carried out using the Systematic Review for Engineering and Experiments (SREE) method. The results show a notable increase in research focused on acid activation over the last few years. The acid activators were always phosphate solutions, mainly phosphoric acid. Metakaolin was the most tested precursor, followed by fly ash, and volcanic ash. The research requires improvements in the methodological quality, providing data on molar ratios (Al/P, Si/Al, and Si/P), Liquid/Solid mass ratio, activator solution molarity, and curing process, in addition to statistical treatment and comparison of results. There exists a paucity of diversity in the examined precursors, activators, and additives. Future research developments need to clarify the behavior of mechanical resistance over time, better curing process, water resistance, durability, and the role of iron, magnesium, and calcium silicates and/or oxides. The paper identifies the main research gaps in the area and functions as a database, guiding researchers in selecting raw materials, dosing methodology, and curing processes.

show abstract

Synthesis of alkali and acid-mediated rGO–metakaolin nano composites for supercapacitor application

Cited by 3 publications

References 41 publications

Influence on Rheology and Microstructure of Nanosilica and Modified Polycarboxylate in Water‐Glass‐Activated Fly Ash/Ground Granulated Blast Furnace Slag Geopolymers

Influence on Rheology and Microstructure of Nanosilica and Modified Polycarboxylate in Water‐Glass‐Activated Fly Ash/Ground Granulated Blast Furnace Slag Geopolymers

Progress towards sustainable energy storage: A concise review

Acid Activation in Low-Carbon Binders: A Systematic Literature Review

Contact Info

Product

Resources

About