Role of Mn Content on the Electrochemical Properties of Nickel-Rich Layered LiNi_{0.8–<i>x</i>}Co_0.1Mn_0.1+<i>x</i>O₂ (0.0 ≤ <i>x</i> ≤ 0.08) Cathodes for Lithium-Ion Batteries

Ni-rich layered oxides (Ni content >60%) are promising cathode candidates for Li-ion batteries because of their high discharge capacity, high energy density, and low cost. However, fast capacity fading, poor thermal stability, and sensitivity to the ambient moisture still plague their mass application. In this work, we systematically investigate the effects of Mn content on the structure, morphology, electrochemical performance, and thermal stability of the Ni-rich cathode materials LiNi_{0.8–<i>x</i>}Co_0.1Mn_0.1+<i>x</i>O₂ (0.0 ≤ <i>x</i> ≤ 0.08). It is demonstrated that with the increase in Mn content and decrease in Ni content, the cycling stability of LiNi_{0.8–<i>x</i>}Co_0.1Mn_0.1+<i>x</i>O₂ to a cutoff charge voltage of 4.5 V is significantly improved. The high-Mn-content electrode LiNi_0.72Co_0.10Mn_0.18O₂ shows a capacity retention of 85.7% after 100 cycles at a 0.2<i> C</i> rate at room temperature, much higher than those of the lower Mn-content samples LiNi_0.80Co_0.10Mn_0.10O₂ (64.0%) and LiNi_0.76Co_0.10Mn_0.14O₂ (72.9%). The improved capacity retention of the high-Mn-content electrode LiNi_0.72Co_0.10Mn_0.18O₂ is due to the stabilization of the electrode/electrolyte interface, as evidenced by the lower solid-electrolyte interphase (SEI) resistance and charge-transfer resistance. Furthermore, with the increase in Mn content and decrease in Ni content, the thermal stability of the Ni-rich cathode is also remarkably enhanced

The Earliest Chinese Proto-Porcelain Excavated from Kiln Sites: An Elemental Analysis

<div><p>In June 2012, the Piaoshan kiln site was excavated in Huzhou, Zhejiang Province, which hitherto proved to be the earliest known Chinese proto-porcelain kiln. Judging from the decorative patterns of unearthed impressed stoneware and proto-porcelain sherds, the site was determined to date to the late Xia (c. 2070–c. 1600 BC), the first dynasty of China. Here, we report on proton-induced X-ray emission analyses of 118 proto-porcelain and 35 impressed stoneware sherds from Piaoshan and five subsequent kiln sites in the vicinity. Using principal components analysis on the major chemical compositions, we reveal the relationships between impressed stoneware and proto-porcelain samples from the six kiln sites. The sherds from different sites have distinctive chemical profiles. The results indicate that the raw materials were procured locally. We find a developmental tendency for early glazes towards mature calcium-based glaze. It is most likely that woody plant ashes with increased calcia-potash ratios were applied to the formula.</p></div

The geographical locations of six kilns in Huzhou and Deqing in Zhejiang province.

<p>The red spots indicate the six kilns mentioned in the text. The base map created using OpenStreetMap, shared under the Open Database Licence (<a href="http://www.opendatacommons.org/licenses/odbl" target="_blank">http://www.opendatacommons.org/licenses/odbl</a>).</p

Date versus silica-alumina ratio in bodies of impressed stoneware and proto-porcelain (wt%).

<p>During Xia and Shang dynasties, the ratio was not stabilized, while the subsequent development witnessed a continuous rise from 4.2 to 5.1.</p

PIXE results of the average chemical compositions (wt%) of the glazes on proto-porcelain sherds from 6 kiln sites.

<p><i>n</i>1: the number of areas considered to be glazed of all the sherds from each site</p><p><i>n</i>2: the number of areas analyzed of all the sherds from each site</p><p><i>n</i>3: the number of the sherds from each site.</p><p>PIXE results of the average chemical compositions (wt%) of the glazes on proto-porcelain sherds from 6 kiln sites.</p

Atomic Resolution Structural and Chemical Imaging Revealing the Sequential Migration of Ni, Co, and Mn upon the Battery Cycling of Layered Cathode

Layered lithium transition metal oxides (LTMO) are promising candidate cathode materials for next-generation high-energy density lithium ion battery. The challenge for using this category of cathode is the capacity and voltage fading, which is believed to be associated with the layered structure disordering, a process that is initiated from the surface or solid-electrolyte interface and facilitated by transition metal (TM) reduction and oxygen vacancy formation. However, the atomic level dynamic mechanism of such a layered structure disordering is still not fully clear. In this work, utilizing atomic resolution electron energy loss spectroscopy (EELS), we map, for the first time at atomic scale, the spatial evolution of Ni, Co and Mn in a cycled LiNi_1/3Mn_1/3Co_1/3O₂ layered cathode. In combination with atomic level structural imaging, we discovered the direct correlation of TM ions migration behavior with lattice disordering, featuring the residing of TM ions in the tetrahedral site and a sequential migration of Ni, Co, and Mn upon the increased lattice disordering of the layered structure. This work highlights that Ni ions, though acting as the dominant redox species in many LTMO, are labile to migrate to cause lattice disordering upon battery cycling, while the Mn ions are more stable as compared with Ni and Co and can act as pillar to stabilize layered structure. Direct visualization of the behavior of TM ions during the battery cycling provides insight for designing of cathode with high structural stability and correspondingly a superior performance

The diagram of principal components analysis on bodies of impressed stoneware and proto-porcelain from three Huzhou kiln sites.

<p>The separated clusters indicate that the raw materials of bodies of impressed stoneware and proto-porcelain from Piaoshan, Beijiashan and Nanshan were from different locations and procured locally. The solid line ellipses represent the 95% confidence limit for each cluster respectively. </p><p><math><mi>PC</mi><mn>1</mn><mo>=</mo><mo>−</mo><mn>0.924</mn><msub><mrow><mi>Na</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>O</mi><mo>+</mo><mn>0.543</mn><mi>MgO</mi><mo>+</mo><mn>0.014</mn><msub><mrow><mi>Al</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>O</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>−</mo><mn>0.152</mn><mi>Si</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>−</mo><mn>0.243</mn><msub><mrow><mi>P</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>O</mi></mrow><mrow><mn>5</mn></mrow></msub><mo>−</mo><mn>0.600</mn><msub><mrow><mi>K</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>O</mi><mo>−</mo><mn>0.464</mn><mi>CaO</mi><mo>+</mo><mn>0.801</mn><mi>Ti</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>+</mo><mn>0.403</mn><mi>MnO</mi><mo>+</mo><mn>0.897</mn><msub><mrow><mi>Fe</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>O</mi></mrow><mrow><mn>3</mn></mrow></msub></math></p><p><math><mi>PC</mi><mn>2</mn><mo>=</mo><mn>0.106</mn><msub><mrow><mi>Na</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>O</mi><mo>+</mo><mn>0.405</mn><mi>MgO</mi><mo>+</mo><mn>0.901</mn><msub><mrow><mi>Al</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>O</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>−</mo><mn>0.960</mn><mi>Si</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>−</mo><mn>0.187</mn><msub><mrow><mi>P</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>O</mi></mrow><mrow><mn>5</mn></mrow></msub><mo>+</mo><mn>0.281</mn><msub><mrow><mi>K</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>O</mi><mo>+</mo><mn>0.334</mn><mi>CaO</mi><mo>−</mo><mn>0.014</mn><mi>Ti</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>−</mo><mn>0.205</mn><mi>MnO</mi><mo>+</mo><mn>0.102</mn><msub><mrow><mi>Fe</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>O</mi></mrow><mrow><mn>3</mn></mrow></msub></math></p><p></p

Map of the location of Huzhou and Deqing.

<p>The red square indicates the area in which the six kiln sites are located. The base map created using the Blue Marble Next Generation with Topography and Bathymetry, July (<a href="http://visibleearth.nasa.gov/view.php?id=73751" target="_blank">http://visibleearth.nasa.gov/view.php?id=73751</a>) [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0139970#pone.0139970.ref023" target="_blank">23</a>].</p

The diagram of principal components analysis on proto-porcelain glazes from six kiln sites.

<p>All the samples from the right-side cluster reach a level of more than 12 wt% in calcium oxide, while the small cluster representing early Huzhou samples is characterized by lower calcium oxide content (< 10 wt%). The confidence ellipses representing the 95% confidence limit for samples from each kiln respectively are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0139970#pone.0139970.s004" target="_blank">S4 Fig</a>. </p><p><math><mi>PC</mi><mn>1</mn><mo>=</mo><mo>−</mo><mn>0.417</mn><msub><mrow><mi>Na</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>O</mi><mo>+</mo><mn>0.814</mn><mi>MgO</mi><mo>−</mo><mn>0.744</mn><msub><mrow><mi>Al</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>O</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>−</mo><mn>0.718</mn><mi>Si</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>+</mo><mn>0.814</mn><msub><mrow><mi>P</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>O</mi></mrow><mrow><mn>5</mn></mrow></msub><mo>−</mo><mn>0.714</mn><msub><mrow><mi>K</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>O</mi><mo>+</mo><mn>0.919</mn><mi>CaO</mi><mo>−</mo><mn>0.242</mn><mi>Ti</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>+</mo><mn>0.648</mn><mi>MnO</mi><mo>−</mo><mn>0.320</mn><msub><mrow><mi>Fe</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>O</mi></mrow><mrow><mn>3</mn></mrow></msub></math></p><p><math><mi>PC</mi><mn>2</mn><mo>=</mo><mo>−</mo><mn>0.468</mn><msub><mrow><mi>Na</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>O</mi><mo>−</mo><mn>0.273</mn><mi>MgO</mi><mo>−</mo><mn>0.330</mn><msub><mrow><mi>Al</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>O</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>+</mo><mn>0.213</mn><mi>Si</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>−</mo><mn>0.224</mn><msub><mrow><mi>P</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>O</mi></mrow><mrow><mn>5</mn></mrow></msub><mo>−</mo><mn>0.319</mn><msub><mrow><mi>K</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>O</mi><mo>−</mo><mn>0.048</mn><mi>CaO</mi><mo>+</mo><mn>0.774</mn><mi>Ti</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>+</mo><mn>0.410</mn><mi>MnO</mi><mo>+</mo><mn>0.455</mn><msub><mrow><mi>Fe</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>O</mi></mrow><mrow><mn>3</mn></mrow></msub></math></p><p></p

Date versus iron(III) oxide in bodies of impressed stoneware and proto-porcelain (wt%).

<p>During Xia and Shang dynasties, the iron(III) oxide level sharply decreased from 4.29 wt% to 2.53 wt%. Afterwards, it maintained a relatively stable level of 2–3 wt%.</p