發(fā)布時(shí)間：2018-06-10 02:22

  本文選題：鋰離子電池 + 鋰電池正極材料�。� 參考：《浙江大學(xué)》2017年碩士論文

【摘要】：目前,商業(yè)上廣泛應(yīng)用的鋰離子正極材料主要有LiCoO_2(LCO)層狀材料、尖晶石型LiMn204(LMO)材料、橄欖石型LiFeP04(LFP)材料和Li[NiCoMn]02(NCM)三元層狀材料。它們有各自的優(yōu)點(diǎn),但也存在相應(yīng)的缺點(diǎn)。LMO具有三維鋰離子通道,工作電壓較高,資源豐富成本較低,環(huán)境友好污染小,尤其是安全性較好,是理想的鋰離子動(dòng)力電池正極材料。然而,LMO可逆循環(huán)容量(110～120mAh/g)偏低,且充放電循環(huán)過(guò)程中由于錳的溶解、電解液分解以及Jahn-Teller效應(yīng)等原因,容量衰減較快。為此,論文引入高容量的第二正極材料,在正極中形成微電池,減少了LMO材料顆粒表面Li+的富集,抑制Jahn-Teller效應(yīng)以保持LMO晶體結(jié)構(gòu)的完整,從而獲得比容量高、長(zhǎng)循環(huán)壽命的鋰離子電池正極材料。研究結(jié)果表明,由高電位LMO與低電位LFP、LCO、NCM材料組成的復(fù)合材料,具有比LMO更高的比容量和更好的循環(huán)壽命。復(fù)合材料放電時(shí)Li+先嵌入高電位LMO,再向低電位材料遷移,LMO顆粒表面富集的Li+嵌入低電位材料,減少了 LMO材料顆粒表面Li+的富集,穩(wěn)定材料結(jié)構(gòu),抑制其產(chǎn)生畸形應(yīng)變。充電過(guò)程中,Li+從低電位材料脫嵌,高電位LMO的Li+,再向低電位材料遷移,形成一種“階段脫鋰”過(guò)程,達(dá)到充電緩沖的目的,從而提升材料的充放電循環(huán)性能。優(yōu)化后的LMO-NCM復(fù)合材料表現(xiàn)出比容量高、倍率性能好、長(zhǎng)循環(huán)壽命的優(yōu)異綜合性能。經(jīng)過(guò)放大實(shí)際生產(chǎn)出了電池模塊,其安全性能和電化學(xué)性能都達(dá)到了國(guó)家標(biāo)準(zhǔn)。市場(chǎng)化應(yīng)用表明,LMO-NCM電池模塊完全達(dá)到預(yù)期性能指標(biāo)。
[Abstract]:At present, LiCoO2LCO-layered materials, spinel LiMn204LMO-based materials, olivine LiFeP04LFP-based materials and Li [NiCoMn] 02NCM-ternary laminated materials are widely used in commercial applications. They have their own advantages, but they also have some disadvantages. LMO has three dimensional lithium ion channels, high operating voltage, low cost of rich resources, less environmental friendly pollution, especially better safety. It is an ideal cathode material for lithium ion power battery. However, the reversible cycle capacity of LMO is low, and the capacity decreases rapidly due to the dissolution of manganese, decomposition of electrolyte and Jahn-Teller effect during charge-discharge cycle. Therefore, a high capacity second cathode material is introduced to form a microcell in the positive electrode, which reduces the concentration of Li on the surface of the LMO particles and suppresses the Jahn-Teller effect to maintain the integrity of the LMO crystal structure so as to obtain high specific capacity. Lithium ion battery cathode material with long cycle life. The results show that the composite composed of high potential LMO and low potential LFP LCONCM has higher specific capacity and better cycle life than LMO. Li intercalated into high potential LMOs during discharge and then migrated to low potential materials. Li embedded in low potential materials reduced Li enrichment on LMO particles, stabilized material structure and inhibited abnormal strain. During charging, Li is deintercalated from low potential material, Li with high potential LMO is transferred to low potential material, which forms a "phase delithium" process, which achieves the purpose of charging and buffering, thus improving the charge and discharge cycle performance of the material. The optimized LMO-NCM composites show high specific capacity, good rate performance and excellent comprehensive properties of long cycle life. After amplifying, the battery module is produced, and its safety and electrochemical performance are up to the national standard. Market application shows that the LMO-NCM battery module fully meets the expected performance targets.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：O646;TM912

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