An advanced cathode composite for co-utilization of cations and anions in lithium batteries

Anions in the electrolyte are usually ignored in conventional"rocking-chair"batteries because only cationic de-/intercalation is considered.An ingenious scheme combining LiMn_(0.7)Fe_(0.3)PO_(4)(LMFP@C)and graphite as a hybrid cathode for lithium-ion batteries(LIBs)is elaborately designed in order to exploit the potential value of anions for battery performance.The hybrid cathode has a higher conductivity and energy density than any of the individual components,allowing for the co-utilization of cations and an-ions through the de-/intercalation of Li^(+)and PF_(6)−over a wide voltage range.The optimal compound with a weight mix ratio of LMFP@C:graphite=5:1 can deliver the highest specific capacity of nearly 140 mA h/g at 0.1 C and the highest voltage plateau of around 4.95 V by adjusting the appropriate mixing ratio.In addition,cyclic voltammetry was used to investigate the electrode kinetics of Li^(+)and PF_(6)−dif-fusion in the hybrid compound at various scan rates.In situ X-ray diffraction is also performed to further demonstrate the structural evolution of the hybrid cathode during the charge/discharge process.