A Multi-Component Additive to Improve the Thermal Stability of Li(Ni1/3Co1/3Mn1/3)O2-Based Lithium Ion Batteries

Abstract

Abstract:To improve the safety of lithium ion batteries, a multi-component (MC) additive (consisting of vinylene carbonate (VC), 1,3-propylene sulfite (PS) and dimethylacetamide (DMAC)) is used in the baseline electrolyte (1.0 M LiPF 6 /ethylene carbonate (EC) + diethyl carbonate (DEC)). The electrolyte with the MC additive is named safety electrolyte. The thermal stabilities of fully charged Li(Ni 1/3 Co 1/3 Mn 1/3 )O 2 (NCM) mixed with the baseline electrolyte and safety electrolyte, respectively, are investigated using a C80 micro-calorimeter. The electrochemical performances of the NCM/baseline electrolyte/Li and NCM/safety electrolyte/Li half cells are evaluated using galvanostatic charge/discharge, cyclic voltammetry and alternating current (AC) impedance. The experimental results demonstrate that the fully charged NCM-safety electrolyte system releases less heat and reduces the main sharp exothermic peak value to a great extent, with a reduction of 40.6%. Moreover, the electrochemical performances of NCM/safety electrolyte/Li half cells are not worse, and are almost as good as that of the NCM/baseline electrolyte/Li half cells.

Additives for Cycle Life Improvement of High‐Voltage LNMO‐Based Li‐Ion Cells

“…[1] However, a combinatorial additive approach expands the sample number dramatically (limited material and/ or number of battery cycle channels). Moreover, each electrode chemistry (more precisely, each electrode composition) requires highly specialized additives to provide best cycling results.…”

“…[1][2][3] However, only very few studies are available which describe indeed full cells which are cycled up to or above 5 V [4] or up to end of life (EOL; at least 80 % discharge capacity) [5] although often electrolytes are entitled as "5 V electrolytes". [1][2][3] However, only very few studies are available which describe indeed full cells which are cycled up to or above 5 V [4] or up to end of life (EOL; at least 80 % discharge capacity) [5] although often electrolytes are entitled as "5 V electrolytes".…”

“…Furthermore, the combination of additives might result in not-predictable effects and cell performances. [1] However, a combinatorial additive approach expands the sample number dramatically (limited material and/ or number of battery cycle channels). Principally, a reference electrolyte is usually working quite good, thus it is very difficult to distinguish small effects, which arise after a few hundred cycles (especially in coin cells or small pouch-bag cells).…”

“…In literature, various additives are mentioned which are able to significantly improve the cycle life, cycle performance and self-discharge. [1][2][3] However, only very few studies are available which describe indeed full cells which are cycled up to or above 5 V [4] or up to end of life (EOL; at least 80 % discharge capacity) [5] although often electrolytes are entitled as "5 V electrolytes". [5,6] One new strategy is a concept to introduce compounds which are able to release additional Li + ions.…”

Interface Modifications by Tris(2,2,2-trifluoroethyl) Borate for Improving the High-Voltage Performance of LiNi1/3Co1/3Mn1/3O2Cathode

“…[24][25][26][27] Instead, introducing functional additives into the electrolyte is proved to be an effective way to prevent the electrolyte decomposition and protect the cathode from structural deterioration, which is mainly benefited by a protective interface film generated on the cathode surface. [28][29][30][31][32][33] It is worth noting that boron-containing compounds as electrolyte additives are effective to improve the high-voltage performance for the layered oxide cathodes, [34][35][36][37] since the boron atom in these compounds can act as anion receptor to coordinate with fluorine anions originated from the byproducts of LiF and HF in the electrolyte. Correspondingly, the ionic conductivity of the interfacial films improved, which is beneficial for the interfacial stability and electrochemical performance enhancement of the cathodes under high operating voltage.…”