本研究針對還原型添加劑磺內酯，1,3-propane sultone (PS) 對鋰離子電池固液界面(Solid Electrolyte Interphase, SEI)膜改質之機制，利用系統性的方法搭配第一原理計算，確認出PS分子穩定之還原狀態，考慮PS分子和環境分子的反應，並分析每一輪反應之產物還原性和反應性。此外將此系統性的方法套入常用電解液EC，並比較其差異。此系統性方法可做為判斷還原型添加劑之依據。
本研究第一部分主要在氣態條件下計算，PS和EC分子在氣態狀態下都不易行還原反應，但其中以PS分子較EC分子更容易行還原反應；考慮兩分子和鋰離子之反應，中性的EC分子較容易和鋰離子鍵結，而還原的PS有較大的趨勢和鋰離子鍵結，且都為自發反應；進一步考慮兩分子之鋰化合物和其他反應物之反應，推測出可能形成SEI膜之成分： (CH2CH2OCO2Li)EC、CH2CH2CH2(OSO2)Li-EC、(OCO2Li)EC 、CH2CH2CH2(OSO2)LiOSO2、(CH2CH2OCO2Li)PS、CH2CH2CH2(OSO2)Li-PS。
第二部分計算均在溶劑狀態下計算，考慮分子的還原反應為一次得到一個電子，在有添加PS分子之情況下，PS分子會優先還原於電解液EC，抑制EC分子分解後之產氣，且PS分子本身不容易還原分解為小分子或產生氣體，產物皆由PS-Li+和其他環境分子反應而成，且都為較大的分子，第三、四輪存在機率最高之產物皆不易進行後續的還原反應；無添加PS添加劑之條件下，還原之EC會分解為C2H4和CO32-兩個較小的分子，且產物皆由CO32-Li+和其他環境分子反應而成，且都以小分子為主，第三、四輪存在機率最高之產物皆容易再進行後續的還原反應。
藉由系統性的方法，提供選擇還原型添加劑的判斷依據，以PS添加劑為例，PS分子本身在行還原反應時不易分解成小分子或氣體，PS分子和其前期的產物有較大的還原能力，後期的產物不利後續的還原，且都為較大的分子；而EC分子之後期產物仍有還原能力，分解後之小分子仍會和鋰離子持續反應。推測此模擬之結果，添加PS分子之情況下，可以降低不可逆電容量之損失，且形成較薄且有效的SEI膜，並提升電池表現。

Systematic method was applied to investigated the effect of reductive-type additive, 1,3-propane sultone (PS) on the formation of solid electrolyte interphase (SEI) at lithium ion battery anode surface, carried by the density functional theory. The anode of graphite as the electron source where the molecules reduced. In the solvent state, the most stable reduction state of PS and electrolyte, EC were confirmed and as the initial reactants reacted with the environment supplies. With the addition of PS, the reduction of PS is prior to EC which would suppress the reduction of EC and decrease the generation of C2H4 gas. In addition, the lithiated compounds from PS- (Li+) are the primary products. The further products from PS- (Li+) are bigger than the products from the reduction of EC. The reduction ability of PS and PS-(Li+) from first and second reaction rounds are higher while the reduction ability of the products from third and fourth reaction are lower than that of EC. The beginning products show higher reduction abilities while the later products show lower reduction abilities, which would be the critical properties for reductive-type additive to form the effective SEI film.

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