A Molecularly Engineered Interface Unlocks Record-Breaking Anode-Free Batteries Introduction

Anode-free lithium metal batteries, which plate lithium directly onto a copper current collector, represent a promising frontier for high-energy storage, offering advantages in cost, manufacturing simplicity, and energy density. However, their practical application has been severely hindered by the poor kinetics and low reversibility of the lithium deposition and stripping process on bare copper, leading to short cycle life and safety concerns.

A groundbreaking study from Shanghai Jiao Tong University and Fudan University, published in Nature Materials, introduces an elegant solution: an ultra-thin interface layer composed of a 2D Polyamide (2DPA) and Lithiated Nafion (LN). Through sophisticated molecular engineering, this layer effectively guides lithium plating, enabling the fabrication of anode-free pouch cells with record-breaking performance.

The 2DPA/LN interphase layer for anode-free lithium metal batteries

A Scalable, Molecularly Engineered Solution

The core of this innovation is the 2DPA, a layered nanosheet with a large conjugated structure and abundant sites (C=O and C=N groups) designed to attract Li-ions. This is then combined with LN, a known ion conductor, to ensure rapid ion transport. The resulting 2DPA/LN film is not only ultra-thin (1.4 nm) but also mechanically robust (11.5 GPa elastic modulus), and critically, it can be applied to copper foil over large areas using scalable methods like blade-coating.

Large-area 2DPA/LN-Cu foil

The "Adsorption-Conjugation" Effect: Guiding Lithium Uniformly

The key to the layer's success is a mechanism the authors term the "adsorption-conjugation synergistic effect." DFT calculations and experimental results confirm that the 2DPA structure acts as a "lithiophilic" guide:

1. Adsorption: The engineered functional groups strongly attract Li-ions from the electrolyte.

2. Distribution: The large conjugated plane of the 2DPA molecule allows these adsorbed ions to spread out evenly.

3. Uniform Nucleation: This process promotes the formation of large, sparsely distributed lithium nuclei, which encourages smooth, flat, and dense lithium deposition instead of the porous, dendritic structures that typically form on bare copper.

This engineered interface also stabilizes the formation of a favorable Solid Electrolyte Interphase (SEI), which is rich in LiF and Li₃N, further enhancing stability and ion transport kinetics.

The effect of the adsorption-conjugation synergy on IHP regulation.

SEI chemistry derived from the 2DPA/LN interphase layer

Breakthrough Electrochemical Performance

The 2DPA/LN interface layer translates directly into dramatic performance gains. In Li||Cu cells, it enabled stable cycling for over 550 cycles with an average Coulombic efficiency of 98.8%. It sustained operation at exceptionally high current densities (up to 30 mA cm⁻²) and high areal capacities (up to 10 mAh cm⁻²).

Electrochemical performance and lithium deposition morphology of Li||2DPA/LN-Cu cells

Most significantly, when paired with a high-capacity NCM811 cathode in a practical 8 Ah anode-free pouch cell, the technology achieved a remarkable energy density of 471 Wh kg⁻¹ and a power density of 622 W kg⁻¹. These values represent a massive leap over previous state-of-the-art anode-free pouch cells, demonstrating the real-world viability of this approach.

Electrochemical performance of anode-free batteries based on 2DPA/LN-Cu

Conclusion and Impact: A New Path for Practical Anode-Free Technology

This work demonstrates that precise molecular engineering of the current collector interface is a powerful and highly effective strategy for overcoming the primary obstacles of anode-free batteries. The 2DPA/LN layer successfully guides lithium plating to be fast, reversible, and uniform, unlocking the true potential of this high-energy-density chemistry.

The outstanding performance achieved in a commercial-scale pouch cell highlights the immense potential of this 2D polymer interface to accelerate the transition of anode-free lithium metal batteries from the laboratory to practical, high-value applications.

The exploration of next-generation fast-charging anodes extends beyond niobium oxides and is a core focus of the battery industry's technological evolution. In this arena, LIMX Power has achieved a key breakthrough, having now mass-produced and commenced bulk deliveries of the industry's first all-silicon-carbon anode battery.

Literature Information

Shuo Wang, Yan Wang, Zhaofeng Ouyang, Shitao Geng, Qianyun Chen, Xiaoju Zhao, Bin Yuan, Xiao Zhang, Shanshan Tang, Qiuchen Xu, Peining Chen, Huisheng Peng, Hao Sun*, Molecular engineering of two-dimensional polyamide interphase layers for anode-free lithium metal batteries, Nature Materials, https://doi.org/10.1038/s41563-025-02339-y