이차전지의 폐자원흐름 분석 및 자원순환성 제고방안

조지혜 ( Ji Hye Jo ),주현수,이소라,김유선 한국환경정책평가연구원 2017 기본연구보고서 Vol.2017 No.-

이차전지란 한 번 사용하고 버리는 일차전지와는 달리 외부의 전기에너지를 화학에너지의 형태로 전환시켜 충·방전이 가능한 전지를 의미한다. 니켈카드뮴전지, 연축전지 등 이차전지의 종류는 다양하나 이 중 리튬이차전지는 스마트폰을 비롯해 블루투스, 드론, 전기차 (EV), 에너지저장장치(ESS) 등에 폭넓게 활용되어 오늘날 전지 시장을 주도하고 있다. 리튬 이차전지 시장은 스마트폰의 상용화를 통해 시장 입지를 다졌으며, 최근 전기차의 급속한 보급과 ESS의 등장에 힘입어 시장규모가 크게 확대되고 있다. 이처럼 급성장하는 이차전지 시장의 속도에 상응하여 효용 만료 및 폐기 등을 통해 폐배터리의 형태로 그 배출 또한 급증할 것으로 전망된다. 하지만 현재 리튬이차전지가 폐기된 이후의 회수 및 관리체계가 미흡한 상황이다. 생산자 책임재활용제도(EPR) 대상 배터리는 수은전지, 산화은전지, 리튬일차전지, 니켈카드뮴전지, 망간/알칼리망간전지, 니켈수소전지만을 대상으로 하고 있어 리튬이차전지는 관리의 사각지대에 있다. 특히 보조배터리, 전기차용 및 ESS용 폐배터리 등은 배출 이후 관리체계 및 처리 가이드라인이 부재한 상황이다. 또한 폐리튬이차전지는 잘못 관리될 경우 폭발 위험성이 높기 때문에 수송 및 처리에 있어 안전성이 요구된다. 현재 리튬이차전지 내 유가금속의 가격이 수요 확대로 인해 급격히 상승하고 있다. 희유 금속인 코발트와 리튬은 양극활물질의 주요 성분으로, 양극활물질은 소재 원가의 40% 상당을 차지하는 핵심 소재이다. 국내 이차전지 업계에서는 코발트와 리튬을 전량 수입에 의존하고 있는 상황으로 국제 유가금속 가격 상승에 매우 취약한 상황이다. 이에 폐리튬이차전지의 자원순환 체계 마련을 통해 유가금속을 효율적으로 회수 및 확보할 수 있도록 정책적으로 지원할 필요가 있다. 해외에서는 자원 회수 및 안전성에 대비한 폐리튬이차전지의 관리체계 구축 및 재활용기술 개발이 활발히 진행되고 있다. 하지만 국내의 경우 리튬이차전지가 배출된 이후 관리흐름에 대한 연구조차 미미한 상황이다. 이에 본 연구에서는 리튬이차전지의 폐자원흐름 분석을 통해 관리현황 및 체계를 파악하고 재활용을 저해하는 문제점을 분석하여 이에 대한 개선방안을 제시하고자 한다. 이를 위해 소형(휴대폰 폐배터리)/중형(전기차 폐배터리)/대형(ESS 폐배터리)을 대상으로 각각 배출단계, ②수거단계, ③전처리단계, ④자원회수단계, ⑤활용단계에 이르는 단계별 흐름을 파악하였다. 또한 향후 발생량 전망을 통하여 희유금속 회수에 따른 수입대체 효과를 산정하고 자원순환성 제고를 위한 배출-수거-전처리-자원회수의 관리기반을 마련하였다. 먼저 소형(휴대폰 폐배터리)의 경우 배출형태는 일체형과 분리형으로 나눌 수 있다. 일체형은 휴대폰에 내장된 채 배출되는 리튬이차전지로 주로 가정에서 배출되며, 휴대폰 유통 및 생산업체에서 배출되는 양은 상당히 미미하다. 가정에서 배출되는 폐휴대폰(폐배터리 포함)은 주로 9가지의 경로 - 새 제품을 구매하는 곳(이동통신사 대리점, 이하 대리점), 캠페인, 상시수거, 위탁회수, 한국정보통신진흥협회(KAIT), 대형마트, 우체국, 민간수집, 중고거래 - 에 해당하는 것으로 나타났다. 이 중 캠페인, 상시수거, 위탁회수, 한국정보통신진흥협회(KAIT) 등에서 회수되는 폐휴대폰은 한국전자제품자원순환공제조합(이하 공제조합)에서 관리되고 있다. 공제조합에서 취합한 폐휴대폰은 수도권자원순환센터(MERC)로 운송되어 본체에서 폐배터리를 분리한 후 이를 재활용업체에 판매하고 있다. 한편, 대리점에서는 중고휴대폰을 구매하여 민간 알뜰폰 사업자(MVNO: Mobile Virtual Network Operators)에게 임대폰으로 판매하거나 해외로 수출하는 것으로 알려져 있다. 공제조합 실무자와의 인터뷰에 따르면, 배출된 전체 폐휴대폰 중 약 98%가 수출되고 있는 것으로 파악된다. 그 밖에도 대형마트, 우체국 역시 최종소비자로부터 일정 금액을 지급하여 중고폰을 구입한 후, 민간업자에게 판매하는 것으로 조사되었다. 수집업체는 사업자 혹은 협회 (한국중고통신유통협회 등)로 나뉘며, 각 기관에서는 민간 대리점, 대형마트, 우체국 등을 통해 수거된 중고 휴대폰을 수출하거나 중고시장에서 거래하고 있다. 중고거래는 전자상거래의 형태로 C2C (Customer to Customer) 혹은 C2B (Customer to Business) 등으로 이루어지고 있다. 한편, 분리형의 경우 배출 및 수거 방식 등에서 일체형과 다른 형태를 지닌다. 배출 주체는 사업장과 수입으로 분류되며, 배터리 제조업체에서 공정 중 부산물의 형태로 배출되거나 미국, 호주, 말레이시아 등에서 분말 및 폐배터리 형태로 수입되고 있다. 중고제품으로 팔리거나 공제조합 등에서 회수하고 있는 일체형과 달리, 분리형은 바로 재활용업체로 운송되어 재활용된다. 수입의 경우 일부 폐배터리는 수입업체를 통해 국내에 반입되어 재활용업체로 운송되며, 나머지 폐배터리 및 분말은 재활용업체에서 직접 수거하고 있다. 재활용업체로 운송된 폐리튬이차전지는 전처리 및 자원회수 공정을 거치게 된다. 이는 소형뿐만 아니라 전기차용 및 ESS용 폐배터리 등 다른 제품 유형의 리튬이차전지에도 동일하게 적용된다. 전처리단계에서는 원료 투입-파쇄-입도분리-자력선별-리튬전지 화합물 회수를 통해 수거된 폐전지를 파쇄해서 분말 형태로 만드는 과정이며, 자원회수 공정에서는 분말로부터 침출-여과-저장-추출의 과정을 통해 코발트, 황산망간, 니켈, 인산리튬, NMC파우더 등을 회수할 수 있다. 추출된 유가금속 중 망간, 코발트, 리튬 등은 결정화 단계를 거쳐 메탈종류로 생산되며, 인산리튬은 탄산리튬 생산 공장을 거쳐 최종적으로 탄산리튬으로 전환 및 생산된다. 이렇게 회수된 유가금속(코발트, 황산망간, 니켈, 인산리튬, 탄산리튬, NMC 파우더)은 전구체 업체, 합금 제조업체, 활물질 제조업체 등에 판매된다. 코발트의 일부는 타이어 관련제품 제조업체에도 납품되고 있다. 다음으로 중형(전기차 폐배터리)의 경우에도 각 단계별로 관리현황을 조사하였다. 국내배출은 ①개인, ②기관, ③사업체, ④제조사 등으로 구분된다. 전기차 소유주는 개인을 의미하나, 현재 국내에서 판매되는 전기차 대부분은 정부 및 지자체 보조금을 받고 있기 때문에 전기차 배터리는 지자체 소유로 구분된다. 기관이란, 공공기관에서 구매한 전기차량을 의미하며, 사업체는 버스회사를 뜻하는 운수업체, 전기택시업체, 렌터카업체, 배터리리스 사업체 등 4가지 유형으로 구분된다. 한편, 폐배터리 형태로 배출되는 분리형은 배터리 제조사와 완성차 제조사에서 주로 공정 중에 발생한다. 소형 배터리와는 달리, 전기차 배터리는 팩 상태로 출시되기 때문에 배터리팩 해체작업이 필요하며, 이는 수작업으로 진행되고 있어 현재는 제조사에서 재활용업체에 처리비용을 지불하고 처리하고 있다. 국내외적으로 전기차 보급이 급격히 늘어갈 것으로 전망되는 가운데, 전기차 배터리 역시 2020년까지 약 200억 달러 시장을 형성하며 크게 성장할 것으로 예측된다. 전기차 배터리는 각 형태에 따라 용량이 다르나, 휴대폰 배터리 기준으로 4,300개의 배터리 용량에 해당한다. 본 연구에서 전기차 폐배터리의 발생량을 추정한 결과, 2017년에는 3대에 불과하나 2025년에는 8,321개의 폐배터리가 발생할 것으로 예측되며, 이는 1,976톤에 해당하는 수치이다. 하지만 현재 「대기환경보전법」에 따라 보조금이 지급된 전기차의 경우 폐차 혹은 수출 등 말소 시 해당 폐배터리를 지방자치단체의 장에게 반납하도록 하고 있으나, 그 이후의 관리체계가 마련되어 있지 않아 현장에서는 혼선을 빚고 있다. 또한 전기차 폐배터리의 경우 발화 및 폭발 가능성이 높아 안전성에 대한 위험성이 지속적으로 제기되고 있으나, 이를 고려한 안전취급 지침 역시 부재한 실정이다. 이에 본 연구에서는 보조금 지급/미지급을 구분하고, 폐차 및 수출 등으로 말소되는 경우 이외에도 운행 중인 전기차 배터리에 대해 한계 효용에 도달했다고 소비자가 판단하는 경우, 교통사고 발생으로 파손의 우려가 있는 경우 등 크게 4가지 사항으로 구분하여 관리체계(안)을 마련하였다. 대형(ESS 폐배터리)의 경우에도 정부로부터 ESS 설치 지원 혹은 전력요금 감면 등을 통하여 보조금이 지급되고 있으나, 이 역시 전기차 폐배터리와 마찬가지로 관리체계가 아직 구축되어 있지 않은 상황이다. 현재 개인 배출 ESS는 주로 가정용 ESS 형태로 배출될 수 있으나, 아직까지 국내 가정용 ESS 보급률은 상당히 낮은 상황이다. 기관의 경우 주로 공공기관에서 사용하고 있으며, 사업체의 경우에는 UPS나 발전소 등에서 주로 사용된다. 지금까지는 ESS 폐배터리의 발생량이 없으나 향후 발생할 경우 지정업체를 통해 수거될 것으로 예상된다. 또한 LG화학, 삼성SDI, 코캄, 인셀, 탑전지 등 ESS 제조사에서 공정 부산물로 발생된 폐배터리 역시 향후 배출 시 재활용업체로 바로 보내질 것으로 판단된다. 상기의 각 제품 유형별로 리튬이차전지의 폐자원흐름을 분석하여 관리상 문제점 및 개선방안을 도출하였다. 우선 소형 폐리튬이차전지(휴대폰 배터리 및 보조배터리 등)에 대해 살펴보면 다음과 같다. A rechargeable (secondary) battery is a battery which can be repeatedly charged by converting the external electric energy into a form of chemical one. Today, the secondary battery has been widely used in mobile phone, Electric Vehicle (EV), Energy Storage System (ESS), etc. However, there are several issues raised on how to manage these waste secondary batteries. Since the Extended Producer Responsibility (EPR) regulation only targets batteries made of mercury, silver-oxide, lithium primary, nickel-cadmium, manganese/ alkaline-manganese, and nickel-hydride, lithium secondary batteries have been untouched for waste management. Moreover, waste battery products like portable chargers, EV battery and ESS battery has no disposal process guideline. Considering the risk of explosion and the trend of increasing price of valuable metals (cobalt, nickel, lithium, etc.) used in the lithium secondary battery, it is necessary to build the safe management and effective resource circulation system. Therefore, we conducted the secondary material flow analysis for the waste lithium secondary batteries. With the analysis, we tried to understand the domestic system of waste lithium secondary battery and find out the bottlenecks in the process of recycling. Lastly, we suggested applicable and improved plans by forecasting the expected amount of the waste lithium secondary battery, and estimated the effect of import substitution by recovering the rare metals. For this work to be done, we set the scope of this study into small size (for mobile), medium size (for EV) and large size (for ESS) of the lithium secondary battery and traced the flow of waste lithium secondary battery in the aspect of 5 stages, which are disposal stage, collection stage, recycling stage, resource recovery stage and utilization stage. For the small size (for mobile) of the lithium secondary battery, the mobile phone battery is to be divided into two types: the battery equipped with the mobile phone and the battery itself. In the stage of the disposal, most of the mobile phones are discarded by household, distributor and manufacturer of the mobile phone. Most of the used mobile phones are collected in 9 routes which are: 1) store where customer purchases new mobile phone, 2) the public campaign, 3) the public permanent collection spot, 4) consignment collection, 5) Korea Association for ICT Promotion (KAIT), 6) large retailers, 7) Post office, 8) private collector and 9) private second hand dealers. After that, some batteries are sent to the recycling center under the management of Korea Electronics Recycling Cooperative (KERC) and 98% of used cell phones are assumed to be sold overseas. The latter one comes from the battery manufacturer or imported from the abroad such as U.S., Australia, and Malaysia, and is directly delivered to the recycling companies which is specialized in handling the waste lithium secondary battery. In the recycling stage, waste mobile phone battery is treated with two sub-processes: 1) preprocessing stage and 2) resource recovery. This recycling process is adapted to the all types of lithium secondary battery. After the preprocessing stage, some of the metals such as cobalt, oxide manganese, nickel and lithium are produced in the resource recovery stage. These recovered metals are sold to the precursor, alloy and cathode active materials manufacturer. Some portion of the recovered cobalt is provided to the certain manufacturer, related to tire products. For the medium size (for EV) of the lithium secondary battery, we also conducted the research on the flow of waste EV battery. EV battery is discarded by car owners, public sectors, business sectors and manufacturers. Most of the owners of EV receive subsidies from the both federal and local governments. Therefore, the battery installed in the vehicle belongs to the local government. Due to increasing EV sales in the global automobile markets, EV battery market is likely to grow in certain extent to the worth two billion by 2020. In this research, we can estimate the expected EV waste battery to be increased significantly to 8,321 by 2025 (which is equivalent to 1,876 ton). According to the 「Clean Air Conservation Act」, the waste batteries subsided by the government are returned to the local government head in the case of scraping or exporting the EV. However, there are no collecting and recycling schemes for the EV waste batteries. Considering the risk of the accidental explosion of the EV battery, we need to establish the safe and effective management system for the EV waste battery. For the large size (for ESS) of waste lithium secondary battery, we also find there are no sound wastes manage schemes in Korea. ESS sold in Korea has been subsided by the government in the forms of supporting the installation or discounting the electricity bill. The ESS waste battery is assumed to be discarded by the household and the public/private sector including the power plants. In these days, the waste batteries produced during the manufacturing process are sent to the recycling company directly. We expect that in few years, the batteries would be discarded by the public or private sectors and treated by authorized center for collecting and recycling the waste. Based on the secondary material flow analysis for each size of the lithium secondary battery, we point out the several management issues and propose the efficient safety strategies. We find five issues regarding on the small type of lithium secondary battery (mobile phone and portable charger) and also come up with four solutions in below. First, there are inaccurate statistical data indicating the domestic flow of mobile waste battery. After the end-users sell their used phones to the retailers, it is difficult to grasp all the detailed flow of them. It indicates that the small lithium secondary battery including portable charger, wireless vacuum cleaner is out of legitimate system. Second, we find that 54.5% of smart phone users still keep their used phones, and we assume that 24 million used-phones are stored at home. The collecting system is not the end-user friendly. Third, there is no safety guideline to collect and transport small lithium secondary battery. Without taping or discharging, explosion risks are considerable for the lithium secondary battery. Fourth, it is difficult to sort the lithium secondary battery into each type. The recycling companies have troubles in sorting the various types of the lithium secondary battery due to lack of the labels indicating the type of cathode active materials used. Lastly, it is necessary to improve the ‘Allbaro’ system to control the imported and exported lithium secondary battery. The level of importing the lithium secondary battery has been significantly increased by years and this is subject to the Basel Convention. This study suggests four solutions to the problems that are mentioned in above. The solutions are: 1) track back schemes by retailers which need to be expanded in the terms of scope and role. The retailers participating in the legitimate collecting program is only 2% of the mobile phone industry in Korea with the results of the low rate in collecting the mobile phone waste battery. In addition, they need to provide their consumer information of collecting the waste lithium secondary batteries, 2) existing legitimate municipal guidelines need to indicate what and how to discard the waste lithium secondary battery under the 「Act on Resource Circulation of Electrical and Electronic Equipment and Vehicles」. Therefore, small size of the waste lithium secondary battery including portable chargers can be safely treated and discarded by the household, 3) the label which symbolizing the type of cathode active materials needs to be attached to the battery itself, 4) the classification of battery type code needs to be modified by adding the specified waste code, in order to appropriately manage them in statistical terms. Next, this study looks into the result of secondary material flow analysis for the medium (for EV) and the large (for ESS) size of the lithium secondary battery and find three issues as well as ten solutions. The issues are: 1) there are no management systems for the EV waste battery. Even though「Clean Air Conservation Act」shows that the subsided EV battery should be returned to the local government head, there is no detailed instructions on collecting and recycling schemes and infrastructures, 2) there are no safe guideline of how to handle the EV waste battery. For many years, the risk of EV battery has been debatable in regard of explosion and low shock resistance, 3) it is difficult to disassemble the waste battery pack. All the bolt and nuts used in those products require hand work system since these are in different shapes depending on the manufacturers, and models of the products. Therefore, recycling companies have difficulty in dismantling those waste products in the recycling stage. In this study, the following 10 aspects of the management problems for EV and ESS waste batteries are examined. 1) Plans for establishment of management system for the subsidized EV waste battery are suggested in the cases ① when the consumer determines that the EV battery has reached its marginal utility, ② when there is a risk of damage due to car accidents, ③ when the registration of vehicle is cancelled by scrapping, and ④ when the owner cancels the registration of vehicle for the export as a used car. 2) There is a necessity of reorganized subsidy withdrawal standard by the characteristics of EV waste batteries. Although the same standard with the reduction devices is appled at present, it is necessary to set the recovery rate that distinguishes the characteristics and the value of the devices. 3) A plan for establishment of management system for the non-subsidized EV waste battery is also suggested, so that it can be also collected into the reuse/recycling system. 4) Establishment of Reuse Center (tentative name) for storage and performance inspection of the waste batteries is examined. The center's functions are collection, performance inspection, processing by inspection results, computerization and accounting. 5) Establishment of new statistical management system for the EV waste battery is needed to complement the missing data of current management system for EV and EV battery. 6) Establishment of legal basis for promoting the recycling of waste battery is reviewed by suggesting complementary measures(Articles) for 「Act on Resource Circulation of Electrical and Electronic Equipment and Vehicles」. 7) Safety guidelines for the control of waste batteries is reviewed for the safe transport and handling of the lithium secondary batteries in accordance with UN ADR(The European Agreement concerning the International Carriage of Dangerous Goods by Road). 8) There is a necessity of improvement standards and methods for ‘Designated Wastes’ by reflecting the characteristics of waste lithium secondary battery. 9) Establishment of the EV battery management department is needed for safe collection and providing relative information. 10) We suggest the safe management system for ESS and promote eco-design for the efficient recycling process. Furthermore, the establishment of cooperation system between battery pack manufacturers and recycling companies is needed for the development of easy-disassembling method for battery pack. The above-mentioned approaches for improvements can significantly contribute to the import substitution of valuable metals such as cobalt and lithium by developing the recycling system for waste batteries. In order to grasp the value of recovered valuable metals in detail, the study examined the import substitution effect of cobalt which has high economic effect. In 2027, estimated recoverable cobalt amounts for cell-phone are about 169 tons, 286 tons for EV and 234 tons for ESS, and the total amount is 689 tons. Based on the average value of imports over the past 5 years, the import substitution effect of cobalt recovered from waste batteries will be about 6% of imported amount in 2027 and about 15% in 2029. The import substitution effect will be significantly increased through the recovery of valuable metals from large waste batteries such as EVs in the near future. Therefore, the efficient resource circulation system for lithium secondary batteries should be established at the earliest passible moment, considering the domestic situation where 90% of minerals are heavily dependent on the imports and the rising prices of the valuable metals such as cobalt and lithium.

A New Concept on Resources Circulation Policy for Electric Vehicles in Korea (Republic of)

( Yong Choi ),( Hyeong-jin Choi ),( Sueng-whee Rhee ) 한국폐기물자원순환학회(구 한국폐기물학회) 2019 ISSE 초록집 Vol.2019 No.-

Globally, advanced countries will be prohibiting the sale of vehicles using internal combustion engine and promoting the supply of electric vehicles in order to reduce fine dust, air pollutants and carbon dioxide from vehicles. In Korea, 430,000 electric vehicles will be supplied by 2022 according to the atmospheric environmental policy. As the market for electric vehicles may be expanding at home and abroad, lithium ion secondary batteries from electric vehicles will be expected to be generated as wastes gradually. The lithium ion secondary batteries contain various valuable materials such as lithium, cobalt, manganese, nickel, iron, etc. According to Korea Mineral Resource Information Service (KOMIS), the price of lithium increased 2.1 times from 7,576 U$/ton in 2015 to 15,534 U$/ton in 2018. The price of cobalt increased 2.5 times from 28,613 U$/ton to 72,824 U$/ton during the same period. Therefore, it is industrially very economical that valuable materials are recovered from the lithium ion secondary battery. In advanced countries, various resources circulation policies are being used to recover and recycle lithium ion secondary batteries in electric vehicles. In the European Union and Japan, the lithium ion secondary batteries are managed by the Expanded Producer Responsibility (EPR) system and a recycling council was established to recycle the lithium ion secondary batteries continuously. Also, China announced regulations on the recycling of lithium ion secondary batteries for vehicles in 2015, strengthening resources circulation capacity for lithium ion secondary batteries. Electric vehicles are being promoted in Korea but the resources circulation policy for lithium ion secondary batteries is insufficient. In this study, the current status of resources circulation policy for lithium ion secondary batteries from electric vehicles in advanced countries is reviewed. In Korea, a new concept on the policy for the activation of resources circulation for lithium ion secondary battery should be introduced step by step including production, consumption, collection and recycling stage. The new concept of resources circulation policy can be applied in many fileds, including the securing of recycling technology, the construction of capacity build, and the establishment of management system such as EPR system.

최근 휴대폰용 배터리의 기술개발 동향

이형근,김영준,조원일,Lee, H.G.,Kim, Y.J.,Cho, W.I. 한국전기화학회 2007 한국전기화학회지 Vol.10 No.1

이 리뷰를 통하여, 휴대폰용 리튬이차전지의 최근 기술동향을 설명하였다. 휴대폰용 이차전지로는 니카드, 니켈-금속수소, 리튬이온 혹은 리튬이온폴리머의 세 가지 형태의 전지가 있으며, 리튬 이차전지가 에너지밀도 측면에서 가장 성능이 우수하다. 즉, 동일한 용량을 갖는 이차전지 가운데 가장 작고 가벼운 것은 리튬이차전지이다. 이러한 리튬이차전지의 시장은 매년 약 15%의 높은 성장을 기록하고 있다. 연구개발은 $LiFePO_4$를 포함하는 새로운 양극, $Li_4Ti_5O_{10}$, Si, 주석 등의 새로운 음극소재, 새로운 전해질과 안정성 확보에 관한 것을 중심으로 진행되고 있다. In this review article, we are going to explain the recent development of lithium secondary batteries for a cellular phone. There are three kinds of rechargeable batteries for cellular phones such as nickel-cadmium, nickel-metal hydride, and lithium ion or lithium ion polymer. The lithium secondary battery is one of the most excellent battery in the point of view of energy density. It means very small and light one among same capacity batteries is the lithium secondary battery. The market volume of lithium secondary batteries increases steeply about 15% annually. The trend of R&D is focused on novel cathode materials including $LiFePO_4$, novel anode materials such as lithium titanate, silicon, and tin, elecrolytes, and safety insurance.

Effect of the dielectric constant of a liquid electrolyte on lithium metal anodes

Kim, Ju Young,Shin, Dong Ok,Chang, Taeyong,Kim, Kwang Man,Jeong, Jiseon,Park, Joonam,Lee, Yong Min,Cho, Kuk Young,Phatak, Charudatta,Hong, Seungbum,Lee, Young-Gi Elsevier 2019 ELECTROCHIMICA ACTA Vol.300 No.-

<P><B>Abstract</B></P> <P>Lithium metal is considered one of the most promising anode materials for realizing high volumetric and gravimetric energy density, owing to the high specific capacity (∼3860 mAh g<SUP>−1</SUP>) and the low electrochemical potential of lithium (−3.04 V vs. the standard hydrogen electrode). However, undesirable dendritic lithium growth and corresponding instability of the solid electrolyte interphase prevent safe and long-term use of lithium metal anodes. This paper presents a simple electrolyte approach to enhance the performance of lithium metal batteries by tuning the dielectric constant of the liquid electrolyte. Electrolyte formulations are designed by changing the concentration of ethylene carbonate to have various dielectric constants. This study confirms that high ethylene carbonate content in a liquid electrolyte enhances the cycling performance of lithium metal batteries because the electric field intensity applied to the electrolyte is reduced in relation to the polarization of the electrolyte and thus allows smooth lithium plating and formation of a stable solid electrolyte interphase. We believe that this approach provides an important concept for electrolyte system design suitable to lithium metal batteries.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Electric field intensity for lithium plating is derived from interface analysis. </LI> <LI> Electrolytes with different dielectric constants are designed systematically. </LI> <LI> Confirmed enhanced cycling performance of lithium occurs with high EC content. </LI> </UL> </P>

리튬이차전지 음극재용 나노입자 Li₄Ti₅O₁₂의 전기화학적 연구

오미현,김한주,김영재,손원근,임기조,박수길,Oh Mi-Hyun,Kim Han-Joo,Kim Young-Jae,Son Won-Keun,Lim Kee-Joe,Park Soo-Gil 한국전기화학회 2006 한국전기화학회지 Vol.9 No.1

리튬이온전지용 음극 활물질로 스피넬 구조의 리튬 티탄산화물$(Li_4Ti_5O_{12})$이 졸겔법과 HEBM법으로 제조되었다. 제조된 $Li_4Ti_5O_{12}$의 입자크기 및 결정구조를 확인하기 위하여 X-선 회절분석(XRD), 주사전자현미경(SEM) 및 평균입자분석(PSA)을 수행한 결과 100nm의 균일한 크기의 입자를 확인하였다. 작업전극으로 $Li_4Ti_5O_{12}$를 사용하고 기준전극과 상대전극으로 lithium 호일을 사용하여 전기화학적인 삼상전극 셀을 구성하여 전기화학적인 특성 평가를 한 결과 $1.0\sim2.5V$의 전압 범위에서 고율 충 방전 성능과 0.2C에서 173mAh/g의 용량 특성을 나타내었다. $Li_4Ti_5O_{12}$은 리튬의 삽입과 탈리가 일어나는 동안 구조적인 안정성을 보여주고 있다. Lithium titanium oxide $(Li_4Ti_5O_{12})$ with spinel-framework structures as anode material for lithium-ion battery was prepared by sol-gel and high energy ball milling (HEBH) method. According to the X-ray diffraction (XRD), Particle Size Analyses(PSA) and scanning electron microscopy (SEM) analysis, uniformly distributed $Li_4Ti_5O_{12}$ particles with grain sizes of 100 nm were observed. Half cells, consisting of $Li_4Ti_5O_{12}$ as working electrode and lithium foil as both counter and reference electrodes showed the high performance of high rate discharge capacity and 173 mAh/g at 0.2C in the range of $1.0\sim2.5 V$. Furthermore, the crystalline structure of $Li_4Ti_5O_{12}$ didn't transform during the lithium intercalation and deintercalation process.

Formation and Inhibition of Metallic Lithium Microstructures in Lithium Batteries Driven by Chemical Crossover

Li, Wangda,Kim, Un-Hyuck,Dolocan, Andrei,Sun, Yang-Kook,Manthiram, Arumugam American Chemical Society 2017 ACS NANO Vol.11 No.6

<P>The formation of metallic lithium microstructures in the form of dendrites or mosses at the surface of anode electrodes (e.g., lithium metal, graphite, and silicon) leads to rapid capacity fade and poses grave safety risks in rechargeable lithium batteries. We present here a direct, relative quantitative analysis of lithium deposition on graphite anodes in pouch cells under normal operating conditions, paired with a model cathode material, the layered nickel-rich oxide LiNi0.61Co0.12Mn0.27O2, over the course of 3000 charge discharge cycles. Secondary-ion mass spectrometry chemically dissects the solid electrolyte interphase (SEI) on extensively cycled graphite with virtually atomic depth resolution and reveals substantial growth of Li-metal deposits. With the absence of apparent kinetic (e.g., fast charging) or stoichiometric restraints (e.g., overcharge) during cycling, we show lithium deposition on graphite is triggered by certain transition-metal ions (manganese in particular) dissolved from the cathode in a disrupted SEI. This insidious effect is found to initiate at a very early stage of cell operation (<200 cycles) and can be effectively inhibited by substituting a small amount of aluminum (similar to 1 mol %) in the cathode, resulting in much reduced transition-metal dissolution and drastically improved cyclability. Our results may also be applicable to studying the unstable electrodeposition of lithium on other substrates, including Li metal.</P>

Lithium/Sulfur Secondary Batteries: A Review

Zhao, Xiaohui,Cheruvally, Gouri,Kim, Changhyeon,Cho, Kwon-Koo,Ahn, Hyo-Jun,Kim, Ki-Won,Ahn, Jou-Hyeon The Korean Electrochemical Society 2016 Journal of electrochemical science and technology Vol.7 No.2

Lithium batteries based on elemental sulfur as the cathode-active material capture great attraction due to the high theoretical capacity, easy availability, low cost and non-toxicity of sulfur. Although lithium/sulfur (Li/S) primary cells were known much earlier, the interest in developing Li/S secondary batteries that can deliver high energy and high power was actively pursued since early 1990’s. A lot of technical challenges including the low conductivity of sulfur, dissolution of sulfur-reduction products in the electrolyte leading to their migration away from the cathode, and deposition of solid reaction products on cathode matrix had to be tackled to realize a high and stable performance from rechargeable Li/S cells. This article presents briefly an overview of the studies pertaining to the different aspects of Li/S batteries including those that deal with the sulfur electrode, electrolytes, lithium anode and configuration of the batteries.

철도차량 용 리튬폴리머 축전지 제어의 효율적 운용 방안

박상헌(Sang-heon Park),이준일(Jun-il Lee),박종익(Jong-ik Park),이상준(Sang-jun Lee) 한국철도학회 2016 한국철도학회 학술발표대회논문집 Vol.2016 No.5

철도차량에는 차량 기동 시와 가선전원 부재 시 전력변환장치 또는 보조전원공급장치로부터 차량 내 제어 전원을 공급할 수 없는 경우 차량에 최소한의 제어 전원을 공급하기 위해 축전지 시스템이 설치된다. 이러한 축전지 시스템은 충방전이 가능한 이차 전지를 적용하고 있으며, 근래에는 이차 전지 기술의 지속적인 발전에 따라 기존 축전지들의 설치 공간적인 제약과 충방전 수명이 개선된 리튬폴리머 축전지 등으로 적용 가능한 축전지 사양이 확장되고 있으며 이러한 리튬폴리머 축전지가 수요처의 요구에 따라 차량에 적용되고 있다. 본 논문에서는 근래에 철도차량에 적용되기 시작한 리튬폴리머 축전지에 대해서 차량 내에서 안정적인 제어를 위한 효율적인 운용 방안에 대해 논하고자 한다. Railway vehicle has a battery system to supply a minimum power source to control the vehicle in case that vehicle control power is not fed from the power conversion device or the auxiliary power supply due that catenary power is not available for or vehicle is in process of starting –up. This kind of battery system is the secondary cell battery rechargeable, such as the lead storage battery or Ni-cd battery, which have been selectively applied according to demanded usage. Also the Lithium-Polymer battery is stated up to be applied according to client’s requirements with continuing development of the secondary cell battery technology in these days. In this connection, the method of efficient operation to control the Lithium-Polymer battery in railway vehicle will be handled in this paper.

Novel Synthesis Method and Electrochemical Characteristics of Lithium Titanium Oxide as Anode Material for Lithium Secondary Battery

Kim Han-Joo,Park Soo-Gil The Korean Institute of Electrical Engineers 2005 KIEE International Transactions on Electrophysics Vol.5C No.3

Lithium titanium oxide as anode material for energy storage prepared by novel synthesis method. Li$_{4}$Ti$_{5}$O$_{12}$ based spinel-framework structures are of great interest material for lithium-ion batteries. We describe here Li$_{4}$Ti$_{5}$O$_{12}$ a zero-strain insertion material was prepared by novel sol-gel method and by high energy ball milling (HEBM) of precursor to from nanocrystalline phases. According to the X-ray diffraction and scanning electron microscopy analysis, uniformly distributed Li$_{4}$ Ti$_{5}$O$_{12}$ particles with grain sizes of 100nm were synthesized. Lithium cells, consisting of Li$_{4}$ Ti$_{5}$O$_{12}$ anode and lithium cathode showed the 173 mAh/g in the range of 1.0 $\~$ 3.0 V. Furthermore, the crystalline structure of Li$_{4}$ Ti$_{5}$O$_{12}$ didn't transform during the lithium intercalation and deintercalation process.

Development of Secondary Battery Market and Trends of Solid-State Batteries

Jae-Sang Parka(박재상),Seung-Taek Myung(명승택) 한국전지학회 2022 한국전지학회지 Vol.2 No.1

현재 이차전지 시장은 전기차의 발전과 함께 급격히 성장중이다. 하지만, 상용화된 리튬 이온전지는, 화재상황에서 유기 전해질의 폭발 위험이 있다. 전고체 전지는 유기용액으로 이루어진 전해질을 고체 전해질로 대체하여 화재 상황에서도 전지의 폭발 위험 등이 없는 안전성이 확보된 전지로 앞으로 전기차 시장의 발전을 위해서는 전고체 전지의 개발이 필수적이다. Currently, the secondary battery market is multiplying along with the development of electric vehicles. However, commercial lithium-ion batteries risk an explosion of the organic electrolyte in a fire situation. The all-solid-state battery replaces the electrolyte made of an organic solution with a solid electrolyte so there is no risk of battery explosion even in a fire situation.