New insights into the Li-storage mechanism in α-Ga2O3 anode and the optimized electrode design

Scalable Synthesis of Ga2O3/N‐Doped C Nanopapers as High‐Rate Performance Anode for Li‐Ion Batteries

“…As show in Figure 4a, both C and Ga 2 O 3 /NC NPs electrodes show main redox peaks in voltage region 0–2 V, suggesting excellent electrochemical compatibility between Ga 2 O 3 and C. As seen, pristine C shows a reduction peak in 1–0 V region in cathodic scan and two oxidation peaks near 0.1 and 1.25 V, which correspond to the intercalation of Li‐ions into C accompanied by the formation of solid electrolyte interface as well as the deintercalation of Li‐ions from C [27] . In contrast, the Ga 2 O 3 /NC NPs electrode shows extra reduction peak near 0.25 V and oxidation peak near 0.78 V from the 2 nd curve afterward, indicating the reduction of Ga 2 O 3 into Ga and the formation of Li 2 Ga alloy as well as the release of Li‐ions from Li 2 Ga and the oxidation of Ga into Ga 2 O 3 [17,24,25] . The charge/discharge curves in Figure 4b coincide with the CV curves, and the main capacity contribution located in voltage region of 0–1.5 V. The pristine NC NPs delivers stable cycling at 0.2 A g −1 , showing charge/discharge capacity of 308/309 mAh g −1 after 200 cycles.…”

“…According to equation of i(V)=k 1 v+k 2 v 1/2 , the capacitive‐contributed charge storage can be extracted by separating the k 1 v part, [51] where k 1 v is constant and can be deduced from CV curves at different scan rates (Figure 6a–d). Note only one couple of reduction/oxidation peaks are observed for all the electrodes at 1.0 mV s −1 , suggesting the lithiation/delithiation process of Ga 2 O 3 and C merges well together [15,25,47] . For fresh Ga 2 O 3 /NC NPs electrode, the capacitive charge storage increases from 32.3 % to 51.0 % along with the increase of scan rate from 0.2 to 1.0 mV s −1 (Figure 6e, i).…”

“…Ni et al. fabricated Ga 2 O 3 micro cuboids/rGO composite, showing discharge/charge capacities of 343.5/334.9 mAh g −1 after 50 cycles at 0.5 A g −1 [25] . Though the cycling performance of Ga 2 O 3 ‐based electrode is improved to a certain extent, the rate performance of Ga 2 O 3 ‐based material is still unsatisfactory, and periodic rate capability has rarely been reported up to now.…”

“…The unsatisfactory reaction kinetics of Ga 2 O 3 mainly correlate with: 1) the intrinsic high bandgap ( E g =4.9 eV) which seriously lowers the electron transfer in Ga 2 O 3 ; [19] 2) the morphology of Ga 2 O 3 is difficult to regulate, which results in modest Li‐ion diffusion [20–22] . To improve the electrochemical performance of Ga 2 O 3 , previous approach mainly focuses on integrating Ga 2 O 3 with various carbonaceous materials, such as amorphous carbon and graphene [15,17,23–25] . For example, Patel et al.…”

Porous Ga2O3 Nanotubes Derived from Urease‐Mediated Interfacially‐Grown NH4Ga(OH)2CO3 for High‐Efficient Hydrogen Evolution

“…Consequently, the green methodologies for massive fabrication of nanotubes are imperative to boost their widespread application.Gallium oxide (Ga 2 O 3 ), [31,32] a nearly direct band gap semiconductor, has found wide applications in optoelectronic devices, [33,34] gas-sensors, [35,36] energy storage, [37,38] photocatalysis, [39,40] photoelectrocatalysis, [41] and solar cells. [42] Numerous morphology of Ga 2 O 3 , including bulk, nanoparticles, nanosheets, nanowires, nanorods, and nanobelts, has been made mainly through GaOOH intermediates. [43] Though nanotubes have many advantages as indicated above, only two researches on Ga 2 O 3 nanotubes were reported, one was fabricated by the Au(Si)-templated CVD for high-temperature nanothermometers, [44] the other was prepared by anodization of Ga metal at −10 °C for generation of hydrogen from water.…”