On-Chip Supercapacitor Silicon Nanostructure Electrode
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing supercapacitors with nanostructure electrodes face challenges in achieving high energy density and capacitance due to weak electric conductivity and sluggish ionic conductivity caused by excessive material deposition, and silicon nanostructures are difficult to protect with effective passivation layers.
Innovation Solution
A ternary composite electrode structure is created using elongated silicon nanostructures coated with a titanium nitride layer as both a protective passivation layer and current collector, combined with a conformal manganese dioxide layer, enhancing surface area and stability through electroless chemical deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If pseudo-capacitive materials are excessively deposited on electrodes to increase capacitance, then the capacitance value increases, but electric conductivity becomes weak and ionic conductivity becomes sluggish
Solution Approach 1:
The electrode is segmented into a hierarchical structure with one-dimensional silicon nanostructures providing the scaffold, TiN coating providing conductive pathways, and MnO2 nanoparticles providing pseudocapacitance. This segmentation allows each component to perform its function optimally without the drawbacks of excessive material deposition.
Solution Approach 2:
A ternary composite material system is employed combining silicon, titanium nitride, and manganese dioxide. The silicon nanostructures provide structural framework, TiN provides electrical conductivity and chemical stability, while MnO2 provides high pseudocapacitance. The composite structure resolves the contradiction by integrating materials with complementary properties.
2Quantity of substance
If silicon nanostructures are used to increase surface area for energy storage, then energy density improves, but chemical stability deteriorates due to corrosion from commercially available electrolytes
Solution Approach 1:
A titanium nitride intermediary layer is introduced between the silicon nanostructures and the electrolyte. This intermediate layer provides chemical stability and corrosion resistance while maintaining electrical conductivity, allowing the silicon nanostructures to function at their full energy storage potential without direct exposure to corrosive electrolytes.
Solution Approach 2:
The titanium nitride coating creates an inert protective environment around the silicon nanostructures, shielding them from the corrosive electrolyte while allowing ionic and electronic transport. This protective barrier enables the silicon-based electrode to maintain both high energy density and chemical stability.
3Reliability
If a passivation layer is applied to protect silicon nanostructures, then chemical stability improves, but fabrication complexity increases due to difficulty in coating one-dimensional nanostructures
Solution Approach 1:
The passivation layer is designed as a porous nanostructured coating that conforms to the one-dimensional silicon nanostructure geometry. This porous structure allows the coating to follow the complex nanoscale morphology of the silicon structures while maintaining protection and conductivity, reducing fabrication complexity compared to attempting to create dense uniform coatings.
4Reliability
If conformal coating is applied to nanostructures to improve capacitor characteristics, then uniformity and performance improve, but manufacturing precision requirements increase
Solution Approach 1:
The coating process parameters are optimized to achieve conformal deposition on one-dimensional nanostructures. By controlling deposition conditions such as temperature, pressure, and material flux, uniform TiN and MnO2 coatings are achieved on the nanoscale silicon structures, improving capacitor characteristics while managing manufacturing precision requirements through parameter optimization.
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
This configuration significantly increases capacitance and energy density, improves mechanical and chemical stability, and maintains uniformity, leading to enhanced performance and retention over charge cycles.
Implementation Method 1
the TiN layer, which is coated on the Si nanostructure, fulfills two technical objects. One is as a protective passivation layer to avoid the corrosion of electrolyte
Implementation Method 2
the TiN layer, which is coated on the Si nanostructure, fulfills two technical objects. One is as a protective passivation layer to avoid the corrosion of electrolyte, and the other is as a current collector
Implementation Method 3
Pseudocapacitors are supercapacitors consisting of both electrical double layer (EDCL) capacitance effect and pseudocapacitance effect, the latter using an electrochemical active material giving an electron charge-transfer between electrolyte and electrode
Implementation Method 4
combined with a conformal manganese dioxide layer, enhancing surface area and stability through electroless chemical deposition
Implementation Method 5
Pseudocapacitors are supercapacitors consisting of both electrical double layer (EDCL) capacitance effect and pseudocapacitance effect
Data Source
AI summary
An on-chip supercapacitor has an electrode that includes one-dimensional silicon nano structures coated with a first layer of titanium nitride. The on-chip supercapacitor also includes a second layer of manganese dioxide deposited on the first layer. An associated method of providing an on-chip supercapacitor electrode on a silicon substrate includes providing a plurality of one-dimensional silicon nanostructures on a substrate, coating the one-dimensional silicon nanostructures with a first layer of titanium nitride, and coating a second layer of manganese dioxide onto the first layer.