Ni-Co4N@NC Supercapacitor Electrode for High Energy and Cycle Stability
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Solution Overview
Problem
Current hybrid supercapacitors face limitations in energy storage capacity due to surface-controlled electrochemical reactions, which restrict charge transfer and are inferior to Li-ion batteries, despite their high power densities and cost-effectiveness.
Innovation Solution
The development of self-supported Ni—Co4N@NC electrodes through nitridation-induced in situ coupling in an N-doped carbon matrix, utilizing a facile pyrolysis of layered Ni—Co hydroxide decorated on polyaniline nanotubes on carbon cloth, enhancing electron transfer and electrochemical activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If surface-controlled electrochemical reactions are used in supercapacitors, then high power density is achieved, but energy storage capacity is limited compared to Li-ion batteries
Solution Approach 1:
The patent employs a composite electrode structure combining Ni-Co4N metal nitride nanoparticles with N-doped carbon nanosheets. This composite design leverages the high power density characteristics of metal nitrides while the conductive carbon matrix provides enhanced energy storage capacity, effectively resolving the contradiction between power and energy storage.
Solution Approach 2:
The electrode structure implements local quality differentiation where Ni-Co4N nanoparticles provide high-power density regions through surface-controlled reactions, while the N-doped carbon matrix provides energy storage regions. This spatial distribution of different functional zones allows simultaneous optimization of both power and energy characteristics.
2Quantity of substance
If Co4N-based electrodes are used to improve energy storage capacity, then electrochemical activity is enhanced, but metastable properties reduce reliability
Solution Approach 1:
The patent uses N-doped carbon nanosheets as a protective shell surrounding the Co4N nanoparticles. This carbon coating stabilizes the metastable Co4N structure, preventing degradation while maintaining its high electrochemical activity, thus resolving the contradiction between enhanced energy storage and structural reliability.
Solution Approach 2:
The composite structure of Ni-Co4N@NC combines the high-capacity Co4N phase with the stable N-doped carbon matrix. This composite design allows the Co4N to contribute its superior electrochemical activity while the carbon matrix provides structural stability and prevents metastability issues.
3Quantity of substance
If N-doped carbon matrix is used to enhance conductivity and active sites, then electrochemical activity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the carbonization process with nitrogen doping into a single thermal treatment step. By incorporating nitrogen-containing precursors into the carbonization process, the N-doped carbon matrix is formed in one operation rather than requiring separate doping steps, thereby reducing manufacturing complexity while maintaining enhanced electrochemical activity.
Solution Approach 2:
The nitrogen-doped carbon matrix serves multiple functions simultaneously: it provides electrical conductivity, creates active sites for electrochemical reactions, and stabilizes the metal nitride nanoparticles. This multi-functionality reduces the need for additional components or processing steps, simplifying manufacturing while enhancing performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The Ni—Co4N@NC electrodes demonstrate high specific energy of 57.2 Wh kg−1 at 843.8 W kg−1 and 89.7% capacity retention after 15,000 cycles, with excellent cycling stability and rate capability, overcoming the energy storage limitations of traditional supercapacitors.
Implementation Method 1
a facile pyrolysis of layered Ni—Co hydroxide decorated on polyaniline nanotubes on carbon cloth
Implementation Method 2
nitridation-induced in situ coupling of Ni—Co4N particles
Implementation Method 3
the charge transfer takes place between adjacent carbon atoms and doped N atoms, which enhances the conductivity
Implementation Method 4
surface controlled electrochemical reactions of supercapacitors restrict the charge transfer process
Data Source
AI summary
There is disclosed a process of producing a hybrid super-capacitor (HSC) electrode, the process comprising performing nitridation-induced in situ coupling of Ni—Co4N nanoparticles in an N-doped carbon matrix, wherein the resultant hybrid super-capacitor (HSC) electrode is a Ni—Co4N@NC electrode. The resultant hybrid super-capacitor (HSC) electrode is a self-supported metal nitride coordinated with N-doped carbon, wherein the nitridation-induced in situ coupling is performed via a facile pyrolysis of layered Ni—Co hydroxide decorated on polyaniline (PANI) nanotubes on the basis of a carbon cloth (CC). Also disclosed is a hybrid supercapacitor cell assembled by employing Ni—Co4N-2@NC as a positive electrode and AC as a negative electrode with a PVA (poly vinyl alcohol)/KOH as a gel electrolyte.