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Prescribing Functional Additives for Treating the Poor Performances of High‐Voltage (5 V‐class) LiNi 0.5 Mn 1.5 O 4 /MCMB Li‐Ion Batteries
Author(s) -
Xu Gaojie,
Pang Chunguang,
Chen Bingbing,
Ma Jun,
Wang Xiao,
Chai Jingchao,
Wang Qingfu,
An Weizhong,
Zhou Xinhong,
Cui Guanglei,
Chen Liquan
Publication year - 2018
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201701398
Subject(s) - materials science , electrolyte , hydrofluoric acid , salt (chemistry) , chemical engineering , flammability , electrode , organic chemistry , composite material , chemistry , metallurgy , engineering
Abstract In this paper, tris(trimethylsilyl) phosphite (TMSP) and 1,3‐propanediolcyclic sulfate (PCS) are unprecedentedly prescribed as binary functional additives for treating the poor performances of high‐voltage (5 V‐class) LiNi 0.5 Mn 1.5 O 4 /MCMB (graphitic mesocarbon microbeads) Li‐ion batteries at both room temperature and 50 °C. The high‐voltage LiNi 0.5 Mn 1.5 O 4 /MCMB cell with binary functional additives shows a preponderant discharge capacity retention of 79.5% after 500 cycles at 0.5 C rate at room temperature. By increasing the current intensity from 0.2 to 5 C rate, the discharge capacity retention of the high‐voltage cell with binary functional additives is ≈90%, while the counterpart is only ≈55%. By characterizations, it is rationally demonstrated that the binary functional additives decompose and participate in the modification of solid–electrolyte interface layers (both electrodes), which are more conductive, protective, and resistant to electrolyte oxidative/reductive decompositions (accompanying active‐Li + consuming parasitic reactions) due to synergistic effects. Specifically, the TMSP additive can stabilize LiPF 6 salt and scavenge erosive hydrofluoric acid. More encouragingly, at 50 °C, the high‐voltage cell with binary functional additives holds an ultrahigh discharge capacity retention of 79.5% after 200 cycles at 1 C rate. Moreover, a third designed self‐extinguishing flame‐retardant additive of (ethoxy)‐penta‐fluoro‐cyclo‐triphosphazene (PFPN) is introduced for reducing the flammability of the aforementioned binary functional additives containing electrolyte.