Ultrafast and Durable Lithium Storage Enabled by Porous Bowl-Like LiFePO4/C Composite with Na+ Doping

Porous bowl-like LiFePO4/C composites are prepared by using the ammonium salt and sodium salt processes with a facile precipitation method coupled with spray-drying technology. Both of the as-prepared LiFePO4/C composites present high crystallinity, bowl-like morphology, and uniform carbon-layer-coated particles. Compared with the traditional ammonium salt process, the sodium salt process, without ammonia nitrogen pollutants, is not only environmentally friendly, but also allows us to introduce appropriate Na+ doping within the resultant LiFePO4. Moreover, the LiFePO4/C composite prepared by using the sodium salt process exhibits better electrochemical performance: a high rate capability (136, 129, and 119 mAh g−1 at 10, 20, and 40 C rate, respectively) and a long cycle stability (60.3 % of initial capacity after 3000 cycles at 10 C, only corresponding to 0.013 % capacity decay per cycle) compared with the other (only exhibits a capacity of 123, 107, and 62 mAh g−1 at rate of 10, 20, and 40 C and retains a 37.5 % of initial capacity after 3000 cycles at 10 C). This good electrochemical performance originates from its special morphology, high crystallinity, stable structure, and Na+ doping.