Boron-Doped Silicon Monoxide Anode for Hybrid Supercapacitors
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Solution Overview
Problem
Existing hybrid supercapacitor systems fail to achieve high energy and power densities simultaneously due to the limitations of anode materials, which lack low working voltage, high specific capacity, excellent rate capability, and long cycling life.
Innovation Solution
A hybrid supercapacitor system featuring a carbon-coated, boron-doped silicon monoxide anode coupled with a highly porous spherical carbon cathode, which enhances energy and power densities through improved cycling stability and rate performance, and is produced without the use of hydrofluoric acid, reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional anode materials (Li4Ti5O12, TiO2, Graphite) are used in hybrid supercapacitors, then cycling stability is improved, but energy density and power density are limited due to high voltage and low capacity
Solution Approach 1:
The patent changes the working voltage parameter of the anode material by selecting silicon-based materials that operate at lower voltages (0-0.5V vs. Li/Li+), enabling the system to utilize a larger voltage window and achieve higher energy density while maintaining good cycling stability through surface modification techniques
Solution Approach 2:
The patent employs composite anode structures combining silicon with carbon materials (such as graphene, carbon nanotubes, or amorphous carbon) to create a composite material that leverages the high capacity of silicon while using the carbon component to provide structural stability and improve cycling performance
2Use of energy by moving object
If graphite anode is used to achieve low lithiation voltage, then energy density is improved, but rate performance and cycling life remain mediocre
Solution Approach 1:
The patent segments the anode material into nanoscale silicon particles or nanostructures, which shortens the diffusion path for lithium ions and electrons, thereby significantly improving rate performance while maintaining low voltage and high capacity characteristics
Solution Approach 2:
The patent utilizes porous carbon structures or hollow spherical configurations to create a three-dimensional network that facilitates rapid ion transport and provides buffer space for volume expansion, enhancing both rate capability and cycling stability
3Use of energy by moving object
If silicon nanostructures are used to achieve high capacity, then energy density is improved, but manufacturing complexity increases due to requiring chemical vapor deposition or HF etching
Solution Approach 1:
The patent replaces expensive and hazardous materials like hydrofluoric acid with simpler, safer, and more cost-effective processing chemicals, using conventional wet chemical etching or thermal decomposition methods that are easier to implement and scale up for commercial production
Solution Approach 2:
The patent employs self-assembly processes or in-situ formation methods where the carbon coating or porous structure forms automatically during the synthesis process, eliminating the need for separate complex fabrication steps and reducing overall manufacturing complexity
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 system achieves high energy density of 128 Wh/kg at 1229 W/kg, retains 89 Wh/kg at ultra-high power density, and demonstrates 70% capacity retention after 6000 cycles, along with a low self-discharge rate, effectively addressing the limitations of prior anode materials.
Implementation Method 1
LIBs can deliver high energy densities (150-250 Wh/kg) by utilizing Faradaic reactions throughout the active materials comprising the batteries
Implementation Method 2
a high-performance lithium-alloy anode, and in particular a supercapacitor with a boron doped lithium-alloy anode
Implementation Method 3
SCs typically offer high power densities (̃10,000 W/kg) because of the fast physical sorption rates of charges on the surfaces of active materials comprising the capacitors
Implementation Method 4
Silicon nanostructures, such as nanowires, nanotubes, and nano/micro-sized particles have been used in hybrid supercapacitors
Data Source
AI summary
Embodiments provide a hybrid supercapacitor exhibiting high energy and power densities enabled by a high-performance lithium-alloy anode coupled with a porous carbon cathode in an electrolyte containing lithium salt. Embodiments include a size reduced silicon oxide anode, a boron-doped silicon oxide anode, and/or a carbon coated silicon oxide anode, which may improve cycling stability and rate performance. Further embodiments include a hybrid supercapacitor system using a Li-active anode in an electrolyte including LiPF6 in a mixture of ethylene carbonate, diethyl carbonate, and dimethyl carbonate (EC:DEC:DMC, 2:1:2 by vol.) and 10 wt % fluoroethylene carbonate (FEC), which may reduce the self-discharge rate.