Exploring a Co-Free, Li-Rich Layered Oxide with Low Content of Nickel as a Positive Electrode for Li-Ion Battery

Abstract

The development of cathode materials represents the key bottleneck to further push the performance of current Li-ion batteries (LIB) beyond the commercial benchmark. Li-rich transition-metal-layered oxides (LRLOs) are a promising class of materials to use as high-capacity/high-potential positive electrodes in LIBs thanks to the large lithium content (e.g., ∼1.2 Li equiv per formula unit) and the exploitation of multiple redox couples (e.g., Mn4+/3+, Co4+/3+, Ni4+/3+/2+). In this work, we propose and demonstrate experimentally a Co-free overlithiated LRLO material with a limited nickel content, i.e., Li1.25Mn0.625Ni0.125O2. This LRLO is able to exchange reversibly an outstanding practical specific capacity at room temperature, i.e., 230 mAh g–1 at C/10 for almost 200 cycles, and can sustain high current rates, i.e., 118 mAh g–1 at 2C. This material has been successfully prepared by a facile solution combustion synthesis and characterized by scanning electron microscopy (SEM), X-ray photoemission spectroscopy (XPS), X-ray absorption near-edge spectroscopy (XANES), X-ray diffraction (XRD), and Raman techniques. Overall, our positive electrodes based on Li1.25Mn0.625Ni0.125O2 overlithiated Co-free LRLO is a step forward in the development of the materials for batteries with improved performance and better environmental fingerprint.

Replacement of Cobalt in Lithium-Rich Layered Oxides by n-Doping: A DFT Study

“…It is important to underline that the formation of single phase LRLO with LNMC08, LNMC04 or similar compositions has been proven in recent experimental reports [54,56,58,67]. In this respect, we can speculate that, despite the unfavorable thermodynamics, the formation of single-phase metastable lattices is likely driven by crystal growth kinetics and the formation of defects (e.g., stacking faults, antisites, dislocations).…”

Understanding the Stability of LiNi0.5Mn0.5O2 as a Co-Free Positive Electrode

“…Layered lithium nickel manganese oxides (LiNi x Mn 1– x O 2 ) are a promising alternative to commercial LiCoO 2 and ternary materials for use as positive electrode materials in lithium-ion batteries (LIBs). , LiNi x Mn 1– x O 2 cathode materials are expected to possess a theoretical capacity as high as that of LiCoO 2 , at approximately 279 mAh g –1 . This prediction is based on the following assumptions: − (1) Nickel and manganese exist as Ni 2+ and Mn 4+ ions in LiNi x Mn 1– x O 2 , respectively. (2) Ni 2+ /Ni 4+ redox pairs contribute to the electrochemical activity, while all lithium ions are extracted, and Mn 4+ ions remain in their state throughout the cycling process.…”

1D confined materials synthesized via a coating method for thermal catalysis and energy storage applications

“…LIBs are extensively applied in all kinds of portable electronic devices such as laptops, mobile phones, and electrical vehicles because of their small size, high energy density, and low cost. 160–162 However, with the increasing demand of high energy density devices and the decreasing of lithium reserves, efforts need to be made to develop other anode materials with high conductivity, high specific capacity, high rates for Li + ion uptake and release as well as small volume changes in addition to the commercial graphite anode. 163–165 Based on the reaction mechanisms, MO or metal sulfide (MS) anode materials of LIBs can be classified into three categories: 166–168 (1) the conversion-type which involves the formation/decomposition of Li 2 O and the reduction/oxidation of metal NPs (MO x + 2 x Li + + 2 x e − ↔ M + x Li 2 O, M = Fe, Co, Ni, Cu, Mn etc.…”