초록 ▼

전지의 고용량, 고출력, 장수명, 고안전성, 저가화의 특성을 달성하기 위하여 전지의 기본 구성 요소인 양극, 음극, 전해질, 분리막, 바인더의 핵심기술 및 선도 신소재 발굴을 위한 기초 연구를 실시하였음.
1) 양극활물질 - Mn을 포함하는 올리빈계 나노구조 양극 활물질 (고용량, 고출력, 저가형)
: 공침법을 이용한 고용량·고밀도 올리빈형 C-LiMn1-xFexPO4 양극소재개발
: 고용량/고밀도 양극활물질 및 새로운 카본 코팅 기술 개발
: 고용량·고밀도 C-LiMn1-xFexPO4 전기화학측정
2)

전지의 고용량, 고출력, 장수명, 고안전성, 저가화의 특성을 달성하기 위하여 전지의 기본 구성 요소인 양극, 음극, 전해질, 분리막, 바인더의 핵심기술 및 선도 신소재 발굴을 위한 기초 연구를 실시하였음.
1) 양극활물질 - Mn을 포함하는 올리빈계 나노구조 양극 활물질 (고용량, 고출력, 저가형)
: 공침법을 이용한 고용량·고밀도 올리빈형 C-LiMn1-xFexPO4 양극소재개발
: 고용량/고밀도 양극활물질 및 새로운 카본 코팅 기술 개발
: 고용량·고밀도 C-LiMn1-xFexPO4 전기화학측정
2) 음극(Ⅰ) - 원자수준 실리콘 클러스터-탄소 고분산 복합체 제조
: 실리콘 나노입자(20nm)를 이용한 그래핀-실리콘 복합 film 및 platelets 제조
: Bottom-up 실리콘-탄소 고분산 복합체 제조를 위한 전구체의 설계 및 선정 연구
3) 음극(Ⅱ) - 탄소재 및 Si/탄소복합계 활물질설계 및 제조 기술개발
: 결정질 흑연 미립분말 조립개념을 적용한 흑연계 탄소재 복합체 설계 및 제조공정 개발
: 다공성 실리콘 core/ 탄소재 코팅층 구조의 Si/탄소 복합계 설계 및 제조공정 개발
4) 바인더 - 고용량/장주기 활물질에 적합한 맞춤형 바인더 개발 (고용량, 장수명)
: 기존의 PVDF 바인더 대비 수십 배 이상의 고접착력을 지니면서 수용성이 가능한 폴리비닐알콜
(PVA) 고분자 바인더 제조 및 응용
: 폴리아크릴로니트릴-부틸아크릴레이트(P(AN-BA))계 수분산 core-shell 바인더 제조 공정 연구
5) 전해질(Ⅰ) - 이온성 액체형 고분자 전해질의 합성 및 전기화학적 특성 분석
: 이온성 액체를 곁사슬로 포함하는 이온성 액체 단량체의 합성 및 전기화학적 특성 분석
6) 전해질(Ⅱ) - 고온내구성 전지용 이온성액체 전해질
: 넓은 전위폭을 갖는 이온성액체 전해질 합성 및 이의 특성 향상방안 확립
7) 분리막 - 미세기공구조제어를 통한 고효율 리튬이차전지용 고안전성/고성능 복합분리막 개발
: 상분리 현상에 기반한 기공구조 제어 및 리튬이차전지용 복합분리막 제조
: 복합분리막 물성 평가 및 전지 적용 및 특성 평가
(출처: 보고서 요약서 3p)

Abstract ▼

Ⅳ. Results
A. Design and development of Olivine-type C-LiMn1-xFexPO4 cathode materials
■ Materials design of Olivine-type LiMn1-xFexPO4 and development of its synthetic method(selection of best co-precipitants)
- Otimization of synthesis conditions and morphology control
- Development of

Ⅳ. Results
A. Design and development of Olivine-type C-LiMn1-xFexPO4 cathode materials
■ Materials design of Olivine-type LiMn1-xFexPO4 and development of its synthetic method(selection of best co-precipitants)
- Otimization of synthesis conditions and morphology control
- Development of high density and capacity (>145 mAh/g) Olivine-type cathode materials with optimized co-precipitation methods
■ Study on the cation substitution in Olivine-LiMn1-xFexPO4
- Improvement in rate capability and cycle life by modification of electrochemical properties with partial substitution of Fe in the structure
- Optimized the Fe content and electrochemical performances of Olivine-LiMn1-xFexPO4

B. Synthesis of highly dispersed atomic-sized silicon clusters in carbon for Li-ion battery anodes
■ Fabrication of Si-graphene composite films & platelets particles
- Fabricated a self-supporting and conductive (18.7 S/cm) thin film(Si 61wt%), which can be used as an electrode as is without conventional components such as current collector, polymeric binder, and conductive additives, and delivered the theoretical capacity of Si with high cycling stability (>1,500 mAh/g, 200 cycles). The Si(35.5wt%)-graphene platelets showed reversible capacity above 800 mAh/g and appreciable rate capability (>500 mAh/g at 100 mA/g) as well.
■ Use of graphene film as a current collector
- The carbon-carbon interfaces were formed by thermal deposition of Si/C precursors on
graphene oxide film. Thus obtained Si/C on graphene film showed much enhanced
cycling stability possibly due to carbon-carbon interfaces b/w active materials and
graphene current collector, which is much lighter than Cu foil
■ Study on the design and selection of Si precursors for bottom-up synthesis of Si/C nanocomposites
- It was found that alkyl-terminated Si nanoparticles (~10 nm) can be synthesized with alkyl-containing Si precurosrs by using solution reduction method. The Si/C core-shell nanocomposites obtained by annealing of alkyl-terminated Si nanoparticles showed promising performances as LIB anodes. The similar chemistry will be applied to prepare highly dispersed Si/C nanocomposites by using a scalable thermo-chemical conversion of the Si precursors containing alkyl-groups.
■ Developed a facile and scalable synthesis method for transition metal oxides/carbon composites, which have high potentials for low cost, high capacity LIB anodes.

C. Development of designing and fabrication method of carbonaceous and Si/carbon composite anode materials.
■ Designing and fabrication of carbonaceous composite anode materials.
- Fabrication of Carbon composite material consisting of graphite particle in an amorphous carbon matrix.
- Fabrication of graphite/carbon composite with porous morphology using graphite fine powder.
■ Designing and fabrication of Si/carbon composite anode materials.
- Fabrication of Si/carbon composite consisting of porous Silicon with fine-graphite and amorphous carbon mixture coating layer

D. Development of environment-friendly binder for high-capacity/long cycle anode materials
■ Development of high molecular weight polyvinyl alcohol binder for high capacity anode materials
- Extremenly high adhesive PVA binder which can be soluble to water
- Significant enhancement for cell performance of high capacity anodes using the PVA binder
■ Nanosized P(AN-BA) binder manufactured using core-shell emulsion polymerization
- Improved cell performance and impedance using the developed P(AN-BA) polymer.

E. Synthesis and electrochemical characterization of vinyl monomers with ionic liquid
■ Synthesis of ionic liquid monomers consisting of vinyl backbone, flexible spacer and pendant ionic liquid
- Synthesis of 1-bromohexyl-6-acrylate from 6-bromo-1-hexanol and acryloyl chloride
- Synthesis of ionic liquid monomers from the reaction with n-methylimidazole and the anion exchange with BF4- ,PF6-
■ Structure analysis using 1H NMR spectra and DSC thermal analysis
- Chemical structure identification of ionic liquid monomer from the 1H NMR spectra
- DSC results : Tg=-115.3 ℃ and Tm=-27.2 ℃
■ Electrochemical characterization of vinyl monomers with ionic liquid
- Ionic conductivity : 1.8 × 10-3 S/cm
- Electrochemical stability : 5.1 V vs Li/Li+

F. Development of ionic-liquid electrolytes for high temperature resistable batteries
■ Synthesis of ionic liquids having wide potential window and improvement of their electrochemical properties for Li ion battery applications.
- Various piperidinium-based ionic liquids have been synthesized and identified by using H-NMR, C-NMR
- Achievement of 5.0V potential window and conductivity of 1×10-3 S/cm
- 50% Mixed ionic liquids performed 99% coulombic efficiency during 30 cycle with cathode half cells.
■ Obtainning flame retardancy of electrolytes by mixing ionic liquids
- mixing 50 wt% methylethylpiperidinium ionic liquids to an electrolyte of EC/DEC(1:!) provides self extinguishing time less than 20 secs
- The 50% ionic liquids preform as good as 100 % carbonate electrolyte at rate capability tests up to 5C

G. Development of High-Safety/High-Performance Composite Separators by Controlling Microporous Structures for High-Efficiency Li-ion Rechargeable Batteries
■ Phase separation-based microporous structure control and its application to composite separators
- Microporous structure of composite separators was controlled by exploiting phase separation
- Mechanism of microporous structure formation was investigated based on the corresponding phase diagram
■ Characterization of composite separators
- Electrochemically stable upto 5 V
- Superior thermal stability due to the incorporation of thermoresistant substrates
- Improved electrolyte wettability
■ Application of composite separators to lithium-ion batteries
- Excellent cell performance due to the well-developed microporous structure and electrolyte wettability of the composite separators
(출처: Summary 9p)

목차 Contents

• 표지 ... 1제출문 ... 2보고서 요약서 ... 3요약문 ... 4SUMMARY ... 8CONTENTS ... 13목차 ... 14제 1장. 연구개발과제의 개요 ... 15 제 1절. 연구개발의 목적 ... 15 제 2절. 연구개발의 필요성 ... 15 제 3절. 연구 개발의 범위 ... 18제 2장. 국내외 기술개발 현황 ... 19 제 1절. 국내 ... 19 제 2절. 국 외 ... 21제 3장. 연구개발수행 내용 및 결과 ... 23 제 1절. 연구 추진 전략 및 접근방법 ... 23 제 2절. 연구 수행내용 및 주요 연구결과 ... 28제 4장. 목표달성도 및 관련분야에의 기여도 ... 64 제 1절. 연구개발 목표의 달성도 ... 64 제 2절. 관련분야에의 기여도 ... 67제 5장. 연구개발결과의 활용계획 ... 69제 6장. 연구개발과정에서 수집한 해외과학기술정보 ... 71 제 1절. 양극 ... 71 제 2절. 음극 ... 71 제 3절. 바인더 ... 71 제 4절. 전해질 ... 72 제 5절. 분리막 ... 72제 7장. 연구시설‧장비 현황 ... 73제 8장. 참고문헌 ... 74끝페이지 ... 75