Affiliation:
1. College of Aerospace Science and Engineering National University of Defense Technology Changsha 410073 China
2. Engineering Research Center of Nano‐Geomaterials of Ministry of Education China University of Geosciences Wuhan 430074 China
3. Key Laboratory of Hydraulic Machinery Transients Ministry of Education School of Power and Mechanical Engineering Wuhan University Wuhan 430072 China
Abstract
AbstractHigh voltage cobalt‐free spinel LiNi0.5Mn1.5O4 (LNMO) is well organized as a high‐power cathode material for lithium (Li)‐ion batteries, however, the weak interaction between the 3d orbital of the transition metal (TM) ions and the 2p orbital of oxygen (O) leads to the instability of crystal structural, hindering the long‐term stable cycling of LNMO cathode especially at high temperatures. Here, a design strategy of orbital interaction is initiated to strengthen TM 3d‐O 2p framework in P‐doped LNMO (P‐LNMO) by choosing phytic acid as P dopant, which can realize more uniform doping compared to regular phosphate. The results show that the enhancement of TM 3d‐O 2p orbital interaction in P‐LNMO can suppress the Jahn–Teller effect and subsequent dissolution of Mn, as well as lowers the energy barrier for Li ion insertion/extraction kinetics. As a result, superior electrochemical performances including high discharge capacity, stable cycling behavior and enhanced rate capability of P‐LNMO are obtained. Significantly, the P‐LNMO pouch cell shows great cycling stability with 97.4% capacity retention after 100 cycles.
Funder
Natural Science Foundation of Hunan Province