Improved performances of lithium-ion batteries by graphite-like carbon modified current collectors

Abstract The current collectors play a key role in the stability, safety and performance of the lithium-ion batteries, so it is of significance to provide a strategy to modify conventional current collectors. Here we develop a graphite-like carbon (GLC) film to modify the copper/aluminum current collectors so as to improve the physical contact and interface characteristics between the current collector and the active materials. The effects of GLC modified current collectors on the performances of LTO and LCO half-cells as well as LTO/LCO full cell were investigated, respectively. The results showed that the discharge capacity was increased and the cycle stability was improved for the LTO and LCO half-cells. Also, the GLC modified current collector was effective to enhance the LTO/LCO full cell. EIS tests presented that GLC modified current collectors could reduce the resistance of LTO half-cell, LCO half-cell, and LTO/LCO full cell. Particularly, GLC modified current collectors caused a great impact on the cycle performances of lithium-ion batteries. After 100 cycles of testing, the capacity retention rate of the P-Cu-LTO battery was only 89.14%, while the capacity retention rate of the GLC-Cu-LTO battery could maintain 93.47%. The capacity retention rate of the P-Al-LCO battery was 64.50%, and the capacity retention rate of the GLC-Al-LCO battery could maintain 92.91%. Moreover, the capacity retention rate of the LTO/LCO battery after 100 cycles of testing was 61.63%, while the GLC film modified LTO/LCO battery capacity retention rate could maintain 88.90%. These indicated that GLC film could provide a feasible approach of modification of current collector to improve the overall performances of lithium-ion batteries.