No abstract

Full cells employing Li 3 VO 4 (LVO) and Li 3 V 2 (PO 4 ) 3 (LVP) as anode and cathode, respectively, are energy storage devices offering high power and cyclability. Such full cells, termed as LVO//LVP, were constructed in this study, and they exhibited low capacity retention (72 %) over 1000 cycles at a high temperature of 50°C. We clarified the capacity degradation mechanism using chargedischarge cycling simulations based on a difference in coulombic efficiency (CE) between two electrodes with/without a capacity decay at electrode materials. Simulation results indicate that the low CE of LVO accompanied with a cyclic capacity decay of LVO was responsible for the full cell capacity degradation. The LVO capacity decay was further elucidated by experimental evidences, showing that the cycled LVO was covered by resistive polymeric films derived from the electrolyte reductive decomposition. Indeed, the capacity retention of full cell cycling was improved to 86-96 % by mitigating the effect of such side reaction, demonstrating the credibility and effectivity of our simple cycling simulation. Our finding may help to elucidate the degradation mode of the full cell cycling with less experimental efforts and work out own strategy to mitigate the degradation.