An Overview of Cation-Disordered Lithium-Excess Rocksalt Cathodes

Chen, Dongchang; Ahn, Juhyeon; Chen, Guoying

doi:10.1021/acsenergylett.1c00203

Cited by 72 publications

(82 citation statements)

References 122 publications

(409 reference statements)

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“…These new synthesis avenues may also offer opportunities to control the material's short range cation ordering which greatly influences performance. [41] Furthermore, fundamental scientific investigations are needed to better understand charge compensation mechanisms in DRX systems. For instance, a variety of DRX cathodes deliver high capacity by leveraging anionic charge compensation, but oxygen gas evolution compromises the materials' reversibility.…”

Section: Drx Cathodesmentioning

confidence: 99%

Next‐Generation Cobalt‐Free Cathodes – A Prospective Solution to the Battery Industry's Cobalt Problem

Muralidharan

Self

Dixit

et al. 2022

Advanced Energy Materials

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manufacturing is increasingly challenged to secure a more resilient and sustainable material supply chain for decades to come.Among those challenges, cobalt stands out as a key ingredient for cathode production and accounts for roughly 25-30% of the overall battery cost. [2] This situation will continue for the next several years, as the state-of-the art Li-ion battery technology is not yet ready to depart from cobalt-containing cathodes, such as LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA) and LiNi x Mn y Co 1−x−y O 2 (NMC). In recent years, cobalt prices have nearly tripled due to increased demand driven by supply chain constraints (Figure 1a), creating unpredictable scenarios for battery manufacturing. Today's cobalt price is nearly 60% higher than that of nickel, the latter being the second most critical element used in LIBs. In a recent report, the Cobalt Development Institute reported that roughly 40% of global cobalt production is directed toward LIBs, and the remaining 60% is geared toward wide range of applications including catalysts, magnets, super alloys, and pigments (Figure 1b). [5] These statistics highlight a scenario where limited availability of cobalt could hinder growth of the EV market.The growth associated with the millions of EVs that are projected to be on the road by 2050 will outpace Co availability in the coming decades. Unless Co-free cathodes and/ or recycling solutions are implemented for EV batteries, Co demand will exceed global cobalt reserves available for battery manufacturing before 2045 (Figure 1c) (this calculation uses metrics from known global cobalt reserves, ≈7 million metric ton total, [6,7] however, if we recompute assuming conservative mining efficiencies of ≈70% and cobalt directed toward battery manufacturing industries to be ≈40%, the total usable battery specific cobalt from the total reserves reduces to ≈2 million metric ton). This alarming scenario clearly illustrates that present-day LIBs are overreliant on cobalt as a critical resource. It is noteworthy to highlight the pivotal role that the U.S. Department of Energy played during the last two decades to reduce LIB cost by nearly eightfold with a goal to further reduce LIB cost to less than $60 kWh −1 by 2030. This new goal requires lowering the cathode's cobalt content to less than 50 mg Wh −1 at the cell level along with other manufacturing cost reductions. If this goal becomes a reality, global battery manufacturers will need a few years to integrate these novel Lithium-ion batteries are overreliant on cobalt containing cathodes. Current projections estimate that hundreds of millions of electric vehicles (EVs) will be on the road by 2050, and this ever-growing demand threatens to deplete global cobalt reserves at an alarming rate. Moreover, cobalt supply chain issues have significantly increased cobalt prices throughout the last decade. As such, energy storage research and development need to reduce the reliance on cobalt to meet ever-growing demand for lithium-ion batteries. The present review summarizes the science ...

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Section: Drx Cathodesmentioning

confidence: 99%

Next‐Generation Cobalt‐Free Cathodes – A Prospective Solution to the Battery Industry's Cobalt Problem

Muralidharan

Self

Dixit

et al. 2022

Advanced Energy Materials

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“…The combined utilization of cationic transition-metal (TM) and anionic oxygen (O) redox processes in Li-excess TM oxides presents new opportunities for the development of highenergy cathode materials for Li-ion batteries (LIBs). [1][2][3] Li-rich Mn-based Li 1+x (Mn,M') 1-x O 2 (x > 0), either forming a layered structure (LMR, M' = Ni, Co, Al etc.) or a cation-disordered rocksalt structure (DRX, M' = d 0 TM such as Nb, Ti, Zr etc.…”

Section: Introductionmentioning

confidence: 99%

Exceptional Cycling Performance Enabled by Local Structural Rearrangements in Disordered Rocksalt Cathodes

Ahn

Satish

et al. 2022

Advanced Energy Materials

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cost and thermal stability of Mn. [4] However, both families of cathodes face significant challenges in maintaining their structural integrity and rate capability upon cycling, with rapid capacity fade, significant voltage hysteresis, and impedance rise often accompanying the gradual transformation in local and/or long-range structure upon Li (de)intercalation. [5][6][7][8] At the material level, side reactions with the electrolyte, TM reduction and dissolution, TM migration and structural transformation as well as irreversible O redox chemistry, have all been suggested to contribute to these issues. [9][10][11][12][13][14][15] To minimize capacity loss in DRX, increasing Mn redox contribution at the expense of O-based redox processes is an effective strategy, as the former chemistry is inherently more reversible than the latter. [15][16][17][18] Fluorine substitution into the O anion sublattice not only stabilizes O redox, as shown by a number of recent studies, [10,[18][19][20][21][22] but also lowers the overall anionic valence and allows for an increased amount of Mn to be incorporated into the material. In contrast to the layered structure, F substitution into the cubic DRX structure can easily be achieved during synthesis. Substitution levels up to 10 at.% and 33 at.% have previously been reported on fluorinated Mn-based DRX samples prepared by solid-state and high-energy ball milling synthesis methods, respectively. [10,18,19,20] Although electrochemical performance improvements have been observed even at low levels of FThe capacity of lithium transition-metal (TM) oxide cathodes is directly linked to the magnitude and accessibility of the redox reservoir associated with TM cations and/or oxygen anions, which traditionally decreases with cycling as a result of chemical, structural, or mechanical fatigue. Here, it is shown that a capacity increase over 125% can be achieved upon cycling of high-energy Mn-and F-rich cation-disordered rocksalt oxyfluoride cathodes. This study reveals that in Li 1.2 Mn 0.7 Nb 0.1 O 1.8 F 0.2 , repeated Li extraction/reinsertion utilizing Mn 3+ /Mn 4+ redox along with some degree of O-redox participation leads to local structural rearrangements and formation of domains with off-stoichiometry spinel-like features. The effective integration of these local "structure-domains" within the cubic disordered rocksalt framework promotes better Li diffusion and improves material utilization, consequently increased capacity upon cycling. This study provides important new insights into materials design strategies to further exploit the rich compositional and structural space of Mn chemistry for developing sustainable, high-energy cathode materials.

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“…This results in cation disordering between Li and transition metals, opening up the pathways for long-range Li-ion diffusion throughout the crystal structure (Figures 10c and d). Li and transition metal ions were randomly distributed at the 4a site in the cationic sublattice (Figure 10b) [127,128]. Unlike conventional layered oxide cathodes, cation disordered rock salts have a wide compositional range.…”

Section: Crystal Structure and Compositionmentioning

confidence: 99%

A Review on High-Capacity and High-Voltage Cathodes for Next-Generation Lithium-ion Batteries

Ghosh¹,

charjee²,

Bhowmik³

et al. 2021

JEPT

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lithium-ion battery (LIB) is at the forefront of energy research. Over four decades of research and development have led electric mobility to a reality. Numerous materials capable of storing lithium reversibly, either as an anode or as a cathode, are reported on a daily basis. But very few among them, such as LiCoO2, lithium nickel manganese cobalt oxide (Li-NMC) variants (LiNi0.33Mn0.33Co0.33O2, LiNi0.5Mn0.3Co0.2O2, LiNi0.6Mn0.2Co0.2O2, and LiNi0.8Mn0.1Co0.1O2), LiNi0.8Co0.15Al0.05O2, LiFePO4, graphite, and Li4Ti5O12 are successful at commercial scale. Future energy requirements demand a push in the energy density of LIBs to meet the criteria of electric aviation, power trains, stationary grids, etc. All these applications have different needs which cannot be satisfied by a particular set of materials. Therefore, various materials need to be utilized in widespread fields of battery applications in the near future. This review discusses potential cathode materials that show a capacity of ≥ 250 mAh g-1 (Li-rich oxides, conversion materials, etc.) or average voltage of ≥ 4 V vs. Li+/Li (polyanionic materials, spinel oxides, etc.). Failure mechanisms, challenges, and way-outs to overcome all the issues are put forward to determine commercial viability.

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An Overview of Cation-Disordered Lithium-Excess Rocksalt Cathodes

Cited by 72 publications

References 122 publications

Next‐Generation Cobalt‐Free Cathodes – A Prospective Solution to the Battery Industry's Cobalt Problem

Next‐Generation Cobalt‐Free Cathodes – A Prospective Solution to the Battery Industry's Cobalt Problem

Exceptional Cycling Performance Enabled by Local Structural Rearrangements in Disordered Rocksalt Cathodes

A Review on High-Capacity and High-Voltage Cathodes for Next-Generation Lithium-ion Batteries

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