Positive Surface Pseudocapacitive Behavior-Induced Fast and Large Li-ion Storage in Mesoporous LiMnPO4@C Nanofibers

Graphical Lithium storage : One-dimensional (1D) LiMnPO 4 @C nanofibers with in situ-created 3D mesoporous architecture are reported, and the charge-storage behavior is addressed. Remarkably, the hierarchical construction promotes the pseudocapacitive contributions. The diffusion-controlled battery-type and surface-controlled capacitive faradaic redox processes act synergistically, giving new insights into Li-storage cathode materials to reach the goal of high energy and power densities simultaneously. Olivine-structured LiMnPO 4 (LMP) is an efficient Li + host owing to its high theoretical energy density and thermal stability. However, its poor ionic and electronic conductivity severely hinder its practical application. Herein, one-dimensional (1D) LMP@C nanofibers with in situ created 3D mesoporous architecture are reported and the charge-storage behavior is addressed. Ultrafine LMP nanoparticles are homogeneously confined in the nanofibers with interconnected and exposed mesoporous intersections, facilitating the electronic/ionic transportation and retarding the pulverization/fracture of electrodes. Remarkably, the hierarchical construction promotes a certain degree of pseudocapacitive contribution. The diffusion-controlled battery-type and surface-controlled capacitive faradaic redox processes act synergistically, giving new insights into Li-ion storage cathode materials to reach the common goal of high energy density and power density simultaneously. The current separation technique suggests surface-dominated pseudocapacitance as the major Li + storage mechanism at high rates, which is regarded as an efficient way to improve the rate performance. Hence, the as-prepared LMP@C nanofibers could deliver a high reversible capacity of 149.8 mAh g −1 with 92 % charge retention over 300 cycles at 0.2 C (1 C=171 mA g −1 ). Even at a high rate of 5 C, a capacity of 63.1 mAh g −1 is retained after 2000 cycles with an exceptional cyclic stability.