Reaction mechanism and additional lithium storage of mesoporous MnO2 anode in Li batteries

Hierarchical α-MnO2nanowires as an efficient anode material for rechargeable lithium-ion batteries

“…Generally, the reaction between transition metal oxides (e.g., MnO 2 ) and Li is typically a conversion-type mechanism. [52] The CV profiles of α-MnO 2 nanowires are in good consistent with reported relevant systems, [53][54][55][56] demonstrating a similar Li storage mechanism is taking place in our system, which as follows:…”

“…[52] A small peak appears at 0.84 V, which corresponds to the reduction of Mn 4+ to Mn 2+ . [55,56] The large intensity peak at approximately 0.07 V during the first cycle can be imputed to reduction of Mn 2+ to Mn 0 . [54,57] In the following delithiation (anodic) process, two distinctive peaks are noticed at 1.31 and 2.08 V, indicating that reversible oxidation of metallic Mn (i.e., Mn 0 to Mn 2 and Mn 2 to Mn 4 ).…”

“…The abnormal high capacity during the 1st discharge is caused by the electrolyte decomposition and the inevitable formation of SEI passivation layer, which is common to most anode materials. [54,56] The long-term cycling stability is also a promising parameter and is measured to determine the strength of the electrode. The galvanostatic charge-discharge technique was employed to evaluate 12 the cycling stability of α-MnO 2 electrode at a current density of 100 mA g -1 in a potential window of 0.05 and 3.0 V. Fig.…”

Challenges and Design Strategies for Conversion-Based Anode Materials for Lithium- and Sodium-Ion Batteries

“…Finally, the capacity is delivered without changing the electronic and local structures of active particles in the low potential region, which is generally called extra capacity. This results in a high capacity over the theoretical value, as in the mesoporous MnO 2 [34]. This extra capacity is attributed to abnormal charge storage reactions [11,46,47] such as electrolyte-derived surface layer [48], interfacial charge storage [49,50], reaction of lithium-containing species [43,51], and/or ion storage in defects/metallic lithium storage [52,53].…”

“…Thus, it is more suitable for observing changes occurring at the nanoscale to explore structure changes during conversion reaction [29][30][31][32][33]. J. Yoon et al investigated the charge storage behavior of mesoporous MnO 2 using Mn K-edge and L-edge XAS [34]. As shown in Mn K-edge Fourier-transformed extended X-ray absorption fine structure (EXAFS) in Fig.…”