Weak Li-O bonds and small grains enable fast ion diffusion and electron transport for LiFePO4 cathode oleh Han-xin Wei, Dao-fa Ying, Jing-ju Liu, Yang Lv, Yu-tao Liu, Jiang-feng Wang, Xuan-lin Gong, Mu-yang Zhou, Zuo-sheng Li, Kuo Chen, Luo-jia Chen, Chuan-ping Wu, Bao-hui Chen