本計畫擬開發獨立電極高電壓電池，透過質譜分析技術解析其電池劣化產物，釐清高電壓電池劣化機制，進而設計最佳之耐高電壓電解液，提升高電壓電池之電池性能。由於本獨立電極不含黏著劑與導電碳材，活性物質與電解液間之電化學反應直接主宰了高電壓環境下電解液劣化行為。電極材料之單純化利於其劣化原因之探究，更有助高電壓電池電解液之開發。研究內容分三年依序執行，第一年將進行高電壓LiN0.5M1.5O4(LNMO)獨立電極的製備以及高電壓電池之建置，探討該電池在各種操作環境下的電池劣化行為。根據電極材料解析與電池電化學分析結果掌握高電壓電池劣化關鍵因素。第二部分是透過質譜分析技術個別鑑定電池之電解液與電極表面劣化產物，總整歸納反應物與劣化產物資訊，進而釐清電池劣化反應機制，並鏈結電池電化學性能變化。此外，也將比較獨立電極與傳統電極高電壓電池所造成在分析結果上的差異。最後一部分則著重在耐高電壓電解液的優化並進行電池效能的驗證。透過電解液添加劑的導入以及電極表面的改質處理，從控制劣化反應機制的角度提升獨立電極高電壓電池之能量密度、功率密度、循環穩定特性乃至安全性。 ;The project aims to analyze degradation products via mass spectrometry techniques, elucidate corresponding degradation mechanisms, and further design an optimum electrolyte for a high-voltage cell composed of self-standing electrodes. Since the self-standing electrode contains no binders and conductive carbons, the electrolyte degradation behavior is directly dominated by electrochemical reaction between active material and electrolyte. Simplifying electrode materials in this specific cell can contribute to investigating cell degradation and developing an optimum electrolyte for a high-voltage battery. The research works are divided into 3 parts (3 years). In the first part, we focus on fabrication of self-standing LiNi0.5Mn1.5O4 (LNMO) electrodes to stablish a high-voltage cell for investigating cell degradation behaviors under various operation conditions. We will discover important factors that dominate cell degradation based on electrode material analysis and cell electrochemical evaluation results. The second part is to utilize mass spectrometry techniques to identify degradation products in electrolyte and on electrode surface. Within the information of reactants and degradation products, we will elucidate reaction mechanisms accounting for the cell degradation, corresponding to deteriorated electrochemical performance. In addition, we will compare the cells composed of self-standing electrodes and conventional electrodes in terms of their degradation products as well as electrochemical performance. In the final part, we will optimize electrolyte for the high-voltage cell and examine its electrochemical performance. Specifically, we try to control degradation reactions by introducing electrolyte additives and modifying electrode surface to improve energy density, power density, cycling stability and safety for the high-voltage cell composed of self-standing electrodes.
