Crystal Water‐Assisted Additional Capacity for Nickel Hydroxide Anode Materials

Abstract

To further increase the energy density of rechargeable batteries to meet the rapidly growing needs of high-energy consuming devices, various materials are tested as anode materials. Some of these newly developed anode materials exhibit anomalously high capacities that exceed their theoretical values. Advanced analytical techniques have revealed that unconventional reaction mechanisms account for these extra capacities. However, despite the potential to take current battery technology development to the next level, research on the utilization of these reactions is currently limited. Herein, a new strategy is proposed to maximize the reaction of -OH components by using crystal water to increase the extra capacity obtained from the abnormal reactions of LiOH species. In addition to the LiOH phase formed by the conversion reaction of metal hydroxides, the H 2 O inside Ni(OH) 2 crystals contributes to the formation of LiOH, which then reacts with lithium. As a result, water-containing Ni(OH) 2 exhibits greater reversible capacities than bare Ni(OH) 2 and NiO, thereby confirming the beneficial effects of crystal water. This novel concept for the enhancement of electrochemical ion storage capacities through the introduction of crystal water to conversion-based anode materials can expand the design factors for maximizing the available capacities of active materials.

Elevating the comprehensive performance of carbon-based hybrid electrode materials by incorporating nickel silicate for lithium-ion capacitors

“…1f show lattice fringes corresponding to (100), (101), and (002) planes of Ni(OH) 2 and (110) plane of Ni 3 Si 2 O 5 (OH) 4 . 30,31 These results reveal the coexistence of Ni(OH) 2 and Ni 3 Si 2 O 5 (OH) 4 in the surface nanosheets of NiSiC.…”

Enhancing Electrochemical Performance of Co(OH)2 Anode Materials by Introducing Graphene for Next-Generation Li-ion Batteries

“…5, the peaks at ~2.20 V in anodic scan and ~1.25 V correspond to the conver-sion reaction. Other peaks from the reaction of the LiOH phase appeared at relatively low potentials, which are marked in the blue region [7,17,38]. Notably, the intensity of the peaks from the conversion and LiOH reactions in the CV curve of Co(OH) 2 / GNP is larger than that of bare Co(OH) 2 , which represents a greater contribution of the two reactions in the composite material.…”

“…The minor changes in the Co K-edge position in the low-potential region indicate that the reversible capacity in the low-potential range did not originate from the conversion reaction. It has been reported that, in this potential region, the LiOH phase formed by the conversion reaction of transition metal hydroxides additionally reacts with lithium, delivering a large additional capacity [7,17,18]. Therefore, the large capacity in the low potential range during charging in Co(OH) 2 /GNP is ascribed to the high contribution of the reversible reaction of LiOH.…”

“…However, commercialized graphite can only theoretically deliver a low capacity of 372 mAh g -1 [4], which cannot satisfy market expectations requiring higher energy and power densities. Accordingly, novel anode materials such as metal oxides [5,6], metal hydroxides [7,8], and silicon-based anodes [9,10] are being investigated as candidates for nextgeneration anode materials. These materials show a significantly high energy density than graphite.…”

Fabrication of mesoporous nickel pyrophosphate electrodes and their transformation to nickel hydroxide with decent capacitance in alkaline media

“…Note that there are two forms of layered nickel hydroxide (aand b-Ni(OH) 2 ). [30][31][32][33][34][35] The a-Ni(OH) 2 is not stable in an alkaline media and transforms into the b-Ni(OH) 2 . [34][35][36][37][38][39] Therefore, it is essential to synthesize b-Ni(OH) 2 with a reduced number of layers in each b-Ni(OH) 2 nanoparticles for a high SC.…”