No abstract

Cotton and sulfuric acid that concentration is 98% as the raw material, to compare the resulting solid carbon sulfonic acid content of the material under different reaction temperatures. FTIR analysis shows that the cotton carbon is an amorphous carbon after sulfonation reactions, a sulfonic acid group present in the resulting material. When the sulfonation temperature is 170 °C, the prepared cotton carbon sulfonic acid has the highest acid content. By the sulfuric acid TG/DTG curve analysis, it verify: 170 °C is the highest activity temperature point of sulfuric acid sulfonation reaction.

Olivine-type LiFePO4 and crystal structure LiMn2O4 or LiNi0.5Mn1.5O4 are promising cathode materials for electric vehicles (EVs) applications. To find more appropriate electrolyte systems to exert the perfect electrochemical performance of LiFePO4, LiMn2O4 and LiNi0.5Mn1.5O4 cathodes, the electrochemical performances of LiBOB-ethylene carbonate (EC)/ethyl methyl carbonate (EMC)/diethyl carbonate (DEC) electrolyte are investigated in this paper. In LiFePO4/Li, LiMn2O4/Li and LiNi0.5Mn1.5O4/Li cells, this novel electrolyte exhibits several advantages, such as stable cycle performance and good rate performance. It suggests that LiBOB-EC/EMC/DEC electrolyte has good compatibility with the three kinds of cathodes, and would be an attractive electrolyte for lithium-ion batteries based upon LiFePO4, LiMn2O4 and LiNi0.5Mn1.5O4 cathodes.

Nano-sized LiNi0.5Mn1.5O4 spines is prepared by a sol-gel reaction at 800 °C in air. Scanning electron microscopic (SEM) image indicates that LiNi0.5Mn1.5O4 has cubic spinel structure with small and homogeneous particles (about 300 nm). Electrochemical test shows that the prepared LiNi0.5Mn1.5O4 delivers up to 125 mAh g− 1at 0.2 C, and the capacity retains 110 mAh g− 1 at 0.5 C after 50 cycles.

Lthium difluoro (sulfato) borate (LiBF2SO4) is a prospecting salt for electrolyte of lithium-ion batteries. The effect of LiBF2SO4 salt on conductivity, charge-discharge capacities, temperature performance, cycling life and storage life at 60 °C is investigated. In graphite half cells at 60 °C, LiBF2SO4-ethylene carbonate (EC)/ dimethyl carbonate (DMC) electrolyte favourably facilitates the formation of a thermal stable, effective and conductive interface film on the surface of carbonaceous anode. Besides, in LiCoO2 half cells at 60 °C, the electrolyte containing the novel salt exerts several advantages, such as stable cycling performance, and good capacity retention performance.