Optimized pseudocapacitance of CoMn2O4@MoO3 nano–microspheres for advanced lithium storage properties

This manuscript introduces the ball-milling and subsequent heat treatment to gain CoMn2O4@MoO3 nano–microsphere composite with optimized pseudocapacitance behavior. The prepared ternary composite material forms the stable core–shell structure as well as realizes fined nanoparticles of the microsphere surface from the slowly thermal decomposition of molybdate. The CoMn2O4@MoO3 hybrid as electrode of the half-cell showing high capacity 1410 mA h g−1 at 0.5 A g−1 after 500 cycles and excellent rate capability (1028 mA h g−1 at 2 A g−1). The experiment results further confirm that b values of CoMn2O4@MoO3 (i = a vb, scan rate v and current i) are over 0.9 in LIBs, indicating an obvious pseudo-capacitive process. Insights into the pathways of this pseudo-capacitive process indicate that Faradaic pseudocapacitance and strong interactions at the two-phase interface of the composite electrode, contributing to optimized electronic environment for enhancing the charge-transfer kinetics and energetics and Li+ storage. Additionally, the core–shell structure relieves volume expansion of nano–microspheres from ion intercalation, benefiting to improve stable cycle. Advanced specific surface area would benefit the penetrated electrolyte with nano–microspheres and expedite electrons/ions transformation, effectively reducing concentration polarization in anode electrode. Specially, the full cell including anode CoMn2O4@MoO3 and cathode LiFePO4 also own excellent electrochemical performance, reflecting the practical application value of the hybrid material for lithium ion battery.