Alpha-voltaic cell is a type of micro nuclear battery that provides several decades of reliable power in the nanowatt to microwatt range, supplying for special applications where traditional chemical batteries or solar cells are difficult to operate. However, the power conversion efficiency of the alpha-voltaic cells reported are still far behind the theoretical limit, making the development of alpha-voltaic cell challenging. Developing advanced semiconductor transducers with higher efficiency in converting the energy of alpha particles into electric energy is proving to be necessary for realizing high-power conversion efficiency. Herein, we propose an alpha-voltaic cell based on SiC PIN transducer that includes a sensitive region with an area of 1 cm², a width of 51.2 μm, and a charge collection efficiency of 95.6% at 0 V bias. We find that optimizing the unintentional doping concentration and crystal quality of the SiC epitaxial layer can significantly increase the absorption and utilization of the energy of alpha particles, resulting in a 2.4-fold enhancement in power conversion efficiency compared with that of the previous study. Electrical properties of the SiC alpha-voltaic cell are measured using an He-ion accelerator as the equivalent α-radioisotopes, with the best power conversion efficiency of 2.10% and maximum output power density of 406.66 nW cm⁻² is obtained. Our research makes a big leap in SiC alpha-voltaic cell, bridging the gap between micro nuclear batteries and practical applications in micro-electromechanical systems, micro aerial vehicles, and tiny satellites.

This work demonstrates a novel polymerization-derived polymer electrolyte consisting of methyl methacrylate, lithium bis(trifluoromethanesulfonyl)imide and fluoroethylene carbonate. The polymerization of MMA was initiated by the amino compounds following an anionic catalytic mechanism. LiTFSI plays both roles including the initiator and Li ion source in the polymer electrolyte. Normally, lithium bis(trifluoromethanesulfonyl)imide has difficulty in initiating the polymerization reaction of methyl methacrylate monomer, a very high concentration of lithium bis(trifluoromethanesulfonyl)imide is needed for initiating the polymerization. However, the fluoroethylene carbonate additive can work as a supporter to facilitate the degree of dissociation of lithium bis(trifluoromethanesulfonyl)imide and increase its initiator capacity due to the high dielectric constant. The as-prepared poly-methyl methacrylate-based polymer electrolyte has a high ionic conductivity (1.19 × 10⁻³ S cm⁻¹), a wide electrochemical stability window (5 V vs Li⁺/Li), and a high Li ion transference number (t_Li⁺) of 0.74 at room temperature (RT). Moreover, this polymerization-derived polymer electrolyte can effectively work as an artificial protective layer on Li metal anode, which enabled the Li symmetric cell to achieve a long-term cycling performance at 0.2 mAh cm⁻² for 2800 h. The LiFePO₄ battery with polymerization-derived polymer electrolyte-modified Li metal anode shows a capacity retention of 91.17% after 800 cycles at 0.5 C. This work provides a facile and accessible approach to manufacturing poly-methyl methacrylate-based polymerization-derived polymer electrolyte and shows great potential as an interphase in Li metal batteries.