Li-rich
layered oxides (LLOs) suffer from severe voltage decay
and capacity fading which have hindered their practical application
for years. Herein, Co-free LLO microspheres with Ni/Mn and Al dual
concentration-gradients are constructed to mitigate the above obstacles.
One concentration-gradient is an electrochemical active gradient (Ni/Mn),
and the other is an electrochemical inert gradient (Al). XPS and soft
and hard XAS after different cycles prove that the combination of
dual concentration-gradients effectively mitigates interfacial reactions,
structural evolution, and the generation of lower-valence Mn3+/Mn4+ or Mn2+/Mn3+ redox couples
during cycling. As a result, the voltage fading rate of LLO cathode
with dual concentration-gradients after 100 cycles is as small as
0.97 mV/cycle at 100 mA g–1. Furthermore, its capacity
retention ratio is also as large as 84.1% after 400 cycles at 300
mA g–1. The combination of dual concentration-gradients
in this work provides a way to develop advanced LLO cathodes for practical
application in the near future.