Quantum defect (QD) is an important issue that demands prompt attention in high-power fiber laser. Large QD may aggravate the thermal load in the laser, which would impact the frequency and amplitude noise, mode stability and threaten the security of high-power laser system. Here, we propose and demonstrate a cladding-pumped Raman fiber laser (RFL) with QD <1%. Using the Raman gain of the boson peak in a phosphorusdoped fiber to enable the cladding pump, the QD is reduced to as low as 0.78% with a 23.7 W output power. To our knowledge, this is the lowest QD ever reported in claddingpumped RFL. Furthermore, the output power can be scaled to 47.7 W with a QD of 1.29%. This work not only offers a preliminary platform for the realization of high-power low-QD fiber laser, but also proves low-QD fiber laser's great potential in power scaling.

Given its competitive theoretical capacity, Bi2MoO6 is deemed as a promising anode material for the realization of efficient Li storage. Considering the severe capacity attenuation caused by the lithiation-induced expansion, it is essential to introduce effective modification. Remarkably, in this work, Bi2MoO6 microsphere with double-layered spherical shells are successfully prepared, and the polyaniline are coated on both inner and outer surfaces of double-layered spherical shells, working as buffer layers to strain the volume expansion during electrochemical cycling. Inspiringly, when utilized as anode in LIBs, the specific capacity of Bi2MoO6@PANI is maintained at 656.3 mAh g–1 after 200 cycles at 100 mA g–1, corresponding to a high capacity of 82%. However, the counterpart of individual Bi2MoO6 is only 36%. This result confirms that the polyaniline layer can dramatically promote stable cycling performances. Supported by in situ EIS and ex situ technologies followed by detailed analysis, the enhanced pseudocapacitance-dominated contributions and electron/ion transfer rate, benefiting from the combination with polyaniline, are further proved. This work confirms the significant effect of polyaniline on the ultrastable energy storage, further providing an in-depth sight on the impacts of polyaniline coating to the electrical conductivity as well as the resistances of electron/ion transport.

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