We have examined the case of light atom (B, N) doped and co-doped graphitic films grown on copper for the anode-free Li Metal Battery (AFLMB) application. For nitrogen doping, the depositions were carried out by laser ablating pure graphite (Gr) in the presence of Nitrogen (N2) or Ammonia (NH3). In another interesting case, 5 wt. % Boron nitride (BN) was added into the graphite target itself to obtain BN-doped graphite films. It was found that the growth condition mediated film constitution and properties significantly influence the Coulombic efficiency and cycling stability of the cells when tested for AFLMB. The cycle life demonstrated by the cells of pure graphitic film (Gr) was only about 110 cycles, while the N-doped graphite films obtained using N2 gas (N2–Gr) exhibited stability up to about 300 cycles. Interestingly the N-doped films obtained using NH3 gas (NH3–Gr) exhibited a stability of 715 cycles and B, N co-doped graphite (BN–Gr) film resulted in an even longer cycle life of 795 cycles. Density functional theory calculations were also performed to deeply understand the interaction and binding energy of Lithium within the undoped and doped graphene sheets modeled through the addition of light elements. It was found that the binding of Li is stronger in the (B, N) co-doped graphene as compared to the N-doped graphene and undoped graphene but much weaker than the B-doped graphene. Therefore, an improved lateral Li diffusion in the (B, N) co-doped graphene is observed where the Li binding strength is optimum resulting in better cycling stability.

中文翻译：

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铜上轻元素（B、N）共掺杂石墨膜作为无阳极锂金属​​电池应用的高强度集流体


我们研究了在铜上生长的轻原子（B、N）掺杂和共掺杂石墨薄膜的情况，用于无阳极锂金属​​电池（AFLMB）应用。对于氮掺杂，沉积是通过在氮气 (N2) 或氨 (NH3) 存在下激光烧蚀纯石墨 (Gr) 进行的。在另一个有趣的案例中，5 wt。将氮化硼（BN）添加到石墨靶本身中以获得BN掺杂的石墨薄膜。结果发现，在进行 AFLMB 测试时，生长条件介导的膜构成和特性显着影响电池的库仑效率和循环稳定性。纯石墨膜（Gr）的电池表现出的循环寿命仅为约110次循环，而使用氮气（N2-Gr）获得的氮掺杂石墨膜表现出高达约300次循环的稳定性。有趣的是，使用NH3气体（NH3–Gr）获得的N掺杂薄膜表现出715次循环的稳定性，而B、N共掺杂石墨（BN–Gr）薄膜则获得了795次循环的更长循环寿命。还进行了密度泛函理论计算，以深入了解通过添加轻元素建模的未掺杂和掺杂石墨烯片中锂的相互作用和结合能。研究发现，与N掺杂石墨烯和未掺杂石墨烯相比，(B，N)共掺杂石墨烯中Li的结合更强，但比B掺杂石墨烯弱得多。因此，在（B，N）共掺杂石墨烯中观察到Li横向扩散得到改善，其中Li结合强度最佳，从而实现更好的循环稳定性。