High Surface Area Electromigration Damage for 3 V Li‐Cell Cathodes

Abstract

A new electrolytic manganese dioxide (EMD) suitable for use as a cathode for primary or secondary Li-cells has been developed. The heat-treated product is a high surface area EMD (HSA EMD), which was prepared by anodic deposition from an MnSO4/H2SO4 electrolyte at a high current density. It shows excellent electrochemical behavior as a cathode for Li cells. This electrode material discharges its theoretical capacity during the first discharge process and has satisfactory cycling behavior. Measurement indicates that HSA EMD has a quicker open-circuit-voltage (OCV) recovery than common EMD. This suggests that fast Li ion diffusion occurs in this material A two or more phase reaction occurs during the first discharge in the Li/HSA EMD cell. In contrast, repeated discharge/charges are fundamentally a single phase reaction. The relationship between the OCV voltage plateau during the first discharge and structure of the HSA EMD is discussed.

Electrodeposition of manganese dioxide: effect of quaternary amines

“…3) were consistent with hexagonal γ-MnO 2 having lattice parameters a = 6.36 Å, b = 10.15 Å, and c = 4.09 Å (ICDD-JCPDS No. 14-0644) [30,31]. The XRD pattern for the sample prepared in the absence of additive yielded diffractive peaks assigned to the (120), (131), (300), (160), and (421) planes.…”

“…3b-d, shown for comparison), suggesting that the quantity of additives does not modify the structure. Note that the broad diffraction peaks in the patterns indicate that crystallite size within the EMD samples is within a range suitable for exploitation of the material for high power applications [31]. A very narrow diffraction peak indicates larger particle sizes, which may not be suitable for rechargeable battery applications due to lower surface area.…”

Correlating Capacity Fading and Structural Changes in Li[sub 1+y]Mn[sub 2−y]O[sub 4−δ] Spinel Cathode Materials: A Systematic Study on the Effects of Li/Mn Ratio and Oxygen Deficiency

“…The detailed synthesis conditions are summarized in Table I. The precise compositions of these five series of samples were determined by chemical analysis 14 and are listed in Table II. Note the Li 1Ϯy Mn 2 O 4Ϯ␦ -type notation used in Table II.…”

Influence of Ti substitution on the structure and electrochemical properties of lithium-excess layered manganese based oxide for lithium ion batteries

“…Consequently, capacity originated from the oxidation of oxide ion can be determined by eliminating the capacity based on TM ions from the total observed capacity. The minimum capacity based on peroxide ion can also be determined since the reduction of Mn to Mn 3+ in Mn based compounds (LiMn 2 O 4 [33], MnO 2 [34][35], Li 1/3 MnO 2 [36], Li 2 O yMnO 2 [37]) have been verified when discharging at 2 V. The capacity that due to the reduction of Mn 4+ to Mn 3+ is also presented in Table 2. The capacity contributed from peroxide ion depends on the composition of the cathode under the assumption that Mn 4+ is reduced to Mn 3+ .…”