LiNi_xFe_yAl_zO_2, a new cobalt-free layered cathode material for advanced Li-ion batteries

摘要

Recently, rapid fluctuations in cobalt prices have created a worsening supply chain constraint that has become a serious cause of concern amidst global battery manufacturers. To address this challenge, here we report a new class of cobalt-free, nickel-rich layered cathode material termed the NFA class with general formula LiNix-FeyAlzO2 (x + y + z = 1). Using co-precipitation reaction in a continuous stirred tank reactor, we synthesized NFA(OH)(2) precursors with the constituent Ni, Fe and Al elements successfully incorporated. The obtained LiNFAO(2) cathode was characterized using X-Ray diffraction, MOssbauer spectroscopy and scanning electron microscopy. Electrochemical behavior was assessed using cyclic voltammetry, galvanostatic charge/discharge, electrochemical impedance spectroscopy and galvanostatic intermittent titration technique at various states of lithiation/delithiation. Electrochemical performance evaluations revealed that our cobalt-free material delivers high capacity of 190 mAh/g at 0.1C. Rate and cycling performance evaluations also indicated good rate capability and cycling stability with 88% capacity retention after 100 cycles at C/3. Using NFA cathodes, we also fabricated a 0.5Ah (C/3) cobalt-free Li-ion battery which demonstrated reasonable cycling stability with similar to 72% capacity retained after 200 cycles. Overall, our work demonstrates the immense potential of the cobalt-free NFA class cathodes as viable candidates towards development of next generation cost effective lithium ion batteries.