Electronically conductive phospho-olivines as lithium storage electrodes

Chung, Sung‐Yoon; Bloking, Jason T.; Chiang, Yet‐Ming

doi:10.1038/nmat732

Cited by 2,811 publications

(1,815 citation statements)

References 25 publications

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“…The origin of the barrier could be explained by phase nucleation where an extra driving force is needed to nucleate the new phase (polysulfides in this system), as observed in other materials with a two-phase reaction before, such as LiFePO 4 . 37 This is further confirmed by the experiment of intentionally adding polysulfide solution into the electrolyte.…”

Section: ■ Results and Discussionmentioning

confidence: 79%

High-Capacity Micrometer-Sized Li₂S Particles as Cathode Materials for Advanced Rechargeable Lithium-Ion Batteries

Yang¹,

Zheng²,

et al. 2012

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Li 2 S is a high-capacity cathode material for lithium metal-free rechargeable batteries. It has a theoretical capacity of 1166 mAh/g, which is nearly 1 order of magnitude higher than traditional metal oxides/phosphates cathodes. However, Li 2 S is usually considered to be electrochemically inactive due to its high electronic resistivity and low lithiumion diffusivity. In this paper, we discover that a large potential barrier (∼1 V) exists at the beginning of charging for Li 2 S. By applying a higher voltage cutoff, this barrier can be overcome and Li 2 S becomes active. Moreover, this barrier does not appear again in the following cycling. Subsequent cycling shows that the material behaves similar to common sulfur cathodes with high energy efficiency. The initial discharge capacity is greater than 800 mAh/g for even 10 μm Li 2 S particles. Moreover, after 10 cycles, the capacity is stabilized around 500−550 mAh/g with a capacity decay rate of only ∼0.25% per cycle. The origin of the initial barrier is found to be the phase nucleation of polysulfides, but the amplitude of barrier is mainly due to two factors: (a) charge transfer directly between Li 2 S and electrolyte without polysulfide and (b) lithium-ion diffusion in Li 2 S. These results demonstrate a simple and scalable approach to utilizing Li 2 S as the cathode material for rechargeable lithium-ion batteries with high specific energy. ■ INTRODUCTIONRechargeable lithium-ion batteries have been widely used in portable electronics and are promising for applications in electric vehicles and smart grids. 1−4 However, due to limited capacity in both electrodes, the specific energy of Li-ion batteries needs to be improved significantly to fulfill the requirements in these applications. 5,6 Significant improvement has been achieved in the development of high-capacity materials to replace carbon-based anodes, such as silicon 7−12 and tin. 13 However, state-of-the-art cathode materials have a capacity less than one-half of the carbon anode. Accordingly, breakthroughs in cathodes are urgently needed to increase the specific energy of lithium-ion batteries. Current metal oxide and phosphate cathodes possess an intrinsic capacity limit of ∼300 mAh/g, with a potential of maximum 130% increase in the specific energy if all the capacity can be used. 14,15 In contrast, Li 2 S has a specific capacity of 1166 mAh/g, four times that of the limit in oxide/phosphate cathodes. 15,16 Considering pairing with Si anodes with 2000 mAh/g capacity, the specific energy of a Li 2 S-based lithium-ion battery could be 60% higher than the theoretical limit of metal oxide/phosphate counterparts ( Figure 1A, see Supporting Information for details) and three times that of the current LiCoO 2 /graphite system. Moreover, Li 2 S could be paired with a lithium-free anode, preventing safety concerns and low Coulomb efficiency of lithium metal in Li/S batteries. 17,18 The main hindrance for utilizing Li 2 S is that it is both electronically and ionically insulating. Therefore, Li 2 S was...

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Section: ■ Results and Discussionmentioning

confidence: 79%

High-Capacity Micrometer-Sized Li₂S Particles as Cathode Materials for Advanced Rechargeable Lithium-Ion Batteries

Yang¹,

Zheng²,

et al. 2012

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“…LIBs for powering electric vehicles and ESS must be safe and have high energy density. To meet these requirements, polyanion compounds1 such as LiFePO 4 phosphates,2, 3 LiMBO 3 borates,4 Li 2 MSiO 4 silicates,5 and Li 2 Fe(SO 4 ) 2 sulfates6 have been developed. These compounds have high structural and thermal stability due to strong covalent bonds with oxygen atoms.…”

Section: Introductionmentioning

confidence: 99%

Fast‐Rate Capable Electrode Material with Higher Energy Density than LiFePO₄: 4.2V LiVPO₄F Synthesized by Scalable Single‐Step Solid‐State Reaction

2015

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Use of compounds that contain fluorine (F) as electrode materials in lithium ion batteries has been considered, but synthesizing single‐phase samples of these compounds is a difficult task. Here, it is demonstrated that a simple scalable single‐step solid‐state process with additional fluorine source can obtain highly pure LiVPO4F. The resulting material with submicron particles achieves very high rate capability ≈100 mAh g−1 at 60 C‐rate (1‐min discharge) and even at 200 C‐rate (18 s discharge). It retains superior capacity, ≈120 mAh g−1 at 10 C charge/10 C discharge rate (6‐min) for 500 cycles with >95% retention efficiency. Furthermore, LiVPO4F shows low polarization even at high rates leading to higher operating potential >3.45 V (≈3.6 V at 60 C‐rate), so it achieves high energy density. It is demonstrated for the first time that highly pure LiVPO4F can achieve high power capability comparable to LiFePO4 and much higher energy density (≈521 Wh g−1 at 20 C‐rate) than LiFePO4 even without nanostructured particles. LiVPO4F can be a real substitute of LiFePO4.

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“…A category of rechargeable lithium batteries that is of great interest is the set of batteries where the cathode material is a lithium iron phosphate (LiFePO 4 ) (6). LiFePO 4 is an environmentally friendly and safe (6). It has a high-lithium intercalation voltage (Â3.5 V relative to lithium metal), high-theoretical capacity (170 mA h g (1 ), low raw materials cost, and stability when used with common electrolyte systems (6).…”

Section: Introductionmentioning

confidence: 99%

“…LiFePO 4 is an environmentally friendly and safe (6). It has a high-lithium intercalation voltage (Â3.5 V relative to lithium metal), high-theoretical capacity (170 mA h g (1 ), low raw materials cost, and stability when used with common electrolyte systems (6). Yet, it also has a key limitation, and that is its extremely lowelectronic conductivity (6).…”

Section: Introductionmentioning

confidence: 99%

“…It has a high-lithium intercalation voltage (Â3.5 V relative to lithium metal), high-theoretical capacity (170 mA h g (1 ), low raw materials cost, and stability when used with common electrolyte systems (6). Yet, it also has a key limitation, and that is its extremely lowelectronic conductivity (6). A feasible way to enhance the intrinsic conductivity is doping alien cations of elements such as Mn, Mg, Ti, and Zr (7).…”

Section: Introductionmentioning

confidence: 99%

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Low-temperature synthesis of a green material for lithium-ion batteries cathode

Mousavi

Bensalem

Gee

2010

Green Chemistry Letters and Reviews

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Battery technology is an important anthropogenic source of the heavy metals which are highly threatening to human health. A category of rechargeable lithium batteries that is of great interest is the set of batteries where the cathode material is a lithium iron phosphate (LiFePO 4 ). LiFePO 4 is an environmentally friendly and safe lithiumion battery cathode material, but it has a key limitation, and that is its extremely low-electronic conductivity, a problem that can be greatly overcome by zinc-doping LiFePO 4 . For the first time to our knowledge, a lowtemperature method, that is advantageous both economically and technologically, for the synthesis of a zincdoped LiFePO 4 is presented. Since the method appears to be applicable for synthesizing various zinc-doped LiFePO 4 compounds with the general formula LiFe 1(x Zn x PO 4 (0 Bx B1), it is very promising for the production of a green cathode material for lithium-ion batteries.

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Electronically conductive phospho-olivines as lithium storage electrodes

Cited by 2,811 publications

References 25 publications

High-Capacity Micrometer-Sized Li₂S Particles as Cathode Materials for Advanced Rechargeable Lithium-Ion Batteries

High-Capacity Micrometer-Sized Li₂S Particles as Cathode Materials for Advanced Rechargeable Lithium-Ion Batteries

Fast‐Rate Capable Electrode Material with Higher Energy Density than LiFePO₄: 4.2V LiVPO₄F Synthesized by Scalable Single‐Step Solid‐State Reaction

Low-temperature synthesis of a green material for lithium-ion batteries cathode

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Electronically conductive phospho-olivines as lithium storage electrodes

Cited by 2,811 publications

References 25 publications

High-Capacity Micrometer-Sized Li2S Particles as Cathode Materials for Advanced Rechargeable Lithium-Ion Batteries

High-Capacity Micrometer-Sized Li2S Particles as Cathode Materials for Advanced Rechargeable Lithium-Ion Batteries

Fast‐Rate Capable Electrode Material with Higher Energy Density than LiFePO4: 4.2V LiVPO4F Synthesized by Scalable Single‐Step Solid‐State Reaction

Low-temperature synthesis of a green material for lithium-ion batteries cathode

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Product

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High-Capacity Micrometer-Sized Li₂S Particles as Cathode Materials for Advanced Rechargeable Lithium-Ion Batteries

High-Capacity Micrometer-Sized Li₂S Particles as Cathode Materials for Advanced Rechargeable Lithium-Ion Batteries

Fast‐Rate Capable Electrode Material with Higher Energy Density than LiFePO₄: 4.2V LiVPO₄F Synthesized by Scalable Single‐Step Solid‐State Reaction