With the rapid development of information technology and e-commerce, online sales have become a mainstream sales trend. According to the 2020 Suning Annual Report, Suning merchandise sales scale was 416.315 billion yuan, of which the online platform merchandise sales scale reached 290.335 billion yuan, an increase of 21.60% year-on-year, with the online sales scale accounting for nearly 70%. Online platforms are increasingly

becoming the mainstream sales channels for electronic products. During the 2020 Tmall “Double Eleven” global shopping event, more than 70 electronic brands, including Apple, Huawei, Xiaomi, Haier, Gree, and so on, had a turnover of over 100 million. After 10 min at zero on “Double Eleven”, the turnover of Huawei phones on JD.com increased by more than 100% year-on-year. In addition to the cell phone category, other digital electronic products such as high-end HiFi headphones, routers, and high-end thin and light notebooks all saw a multi-fold growth in sales.

Today, more and more consumers are switching from offline shopping to online, and more and more manufacturers are relying on online platforms to sell their products. The advantages of platform sales over traditional offline sales are obvious, as consumers can purchase products without being bound by time and place. In addition, online platforms can use the network effect of their own channels or adopt online marketing to expand the potential demand of the consumer market, which is the unique “platform power” of platform sales ^[1]. For example, Tmall and Taobao hired influential celebrities and weblebrities to broadcast live to promote their products. There is the augmented reality (AR) experience function launched by Dewu APP, which reduces the uncertainty of consumers when purchasing products online. “Platform power” enables online retail platforms to create more demand through their online channels and attract more manufacturers to sell products through the platform ^[2].

There are mainly two modes of cooperative sales between the manufacturer and platforms, namely the platform reselling model (by purchasing products from the manufacturer and selling them to buyers) and the platform agent selling model (in which the manufacturer sells their products directly to buyers). Platform agent reselling is where the platform receives a commission or a portion of sales from the manufacturer, who sells directly to the consumer ^[3]. In the case of electronics, consumers demand electronics more frequently. Therefore, most platforms use a reselling model when selling electronics in order to gain pricing power over them and thus have better control over price as a marketing lever ^[4]. For example, Amazon resells high-demand products such as electronics produced by upstream manufacturers, while it adopts the agent reselling model for non-mainstream, long-tail products ^[5].

Electronics are different from general durable products. With the rapid development of electronic technology, the replacement of electronic products is extremely fast. Although it can bring uspeople an improvement in the quality of life, the frequency of elimination is higher than that of other products. If the discarded electronic products cannot be disposed of in time, it will bring serious pollutive damage to the ecological environment. For example, lead in televisions, and arsenic, mercury, and other harmful substances contained in computers, are extremely harmful to the environment. However, there are many reusable and even non-renewable resources in waste electronic products, such as aluminum alloys in computer hard drives, and lithium or nickel-metal hydride batteries in communication tools, which can be recycled and reused. Electronic products are products with high recycling value, which have three attributes of fast replacement, environmental pollution, and resource reuse. Therefore, in order to reduce the impact of waste electronics on the environment, it is very important to properly recycle waste electronics ^[6]. Now, many companies have started to recycle these reusable waste electronic products. The recycling of waste electronic products is a problem to be solved in practice and theory. The first and foremost problem to be solved for waste electronic products is the choice of recycling model for the manufacturer. There are two main types of manufacturer recycling: one is self-recycling by the manufacturer, and the other is with the help of online platforms or third-party recycling. The manufacturer’s independent recycling is in direct contact with consumers and can keep up with the latest product trends and retain accurate information feedback, thus making the production and sale of products and reverse recycling more efficient while also maximizing residual value profits. For example, BYD independently recycles lithium power batteries in electric vehicles. There are also many cases of the manufacturer using online platforms or third parties for recycling. For example, Aihuishou, as one of the electronic product-recycling platforms, cooperates with Huawei, Xiaomi, Apple, oppo, and other mobile phone manufacturers to recycle waste electronic products. Haier, TCL, Skyworth, and other home appliance companies use third-party recycling service platforms, combined with their own sales channels and networks, to carry out used-product recycling and trade-in services across the country with the operation idea of “Internet + recycling”. Unlike traditional offline recycling, online recycling is becoming an important recycling method for the manufacturer because it reaches a wider range of consumers and is more convenient for them. For the manufacturer, both recycling models have their advantages. At present, however, the incentive for the manufacturer to recycle themselves or through platforms remains unclear, especially for electronic products with environmental pollution and high recycling value. Therefore, the selection of a recycling model of waste electronic products is one of the key points discussed in this paperntry.

In addition to the choice of recycling model, the opaque recycling process, lax supervision, and other problems easily affect consumers’ trust in the recycling of waste products. Consumers returned used products, but not all of them reached the manufacturer, and the actual recycling of waste products was far less than the theoretical recycling. It is reported that, in 2020, the theoretical recycling amount of lithium ion batteries in the Chinese market reached 478,000 tons, but that the actual recycling amount was only 196,000 tons, accounting for only 41% of the theoretical recycling amount. Such false recycling problems will cause consumers to no longer trust the product, which can affect the brand goodwill of the product and reduce consumers’ willingness to recycle. In fact, the effective recycling of waste electronic products restricts the key bottleneck of recycling waste electronic products. As a distributed accounting technology, blockchain has the characteristics of visibility, tamper-proof, traceability, decentralization, and the high reliability of the system, which can verify transactions on peer-to-peer networks and achieve security, transparency, low transaction costs, and the automation of transactions [7–9] ^[7][8][9]. WResearchers can increase the trust of consumers by using the visibility and traceability features of blockchain technology to enable the real and effective recycling of waste products. At present, some enterprises have applied blockchain technology in the recycling process of waste products. For example, BASF ag in Canada has increased the recycling utilization of plastic products and improved the circularity of its supply chain through reciChain, a distributed ledger blockchain platform. Moreover, because of reciChain’s transparency, the platform can better assure brand owners that their recycling certificates are valid, thereby increasing consumer trust. The recycling and treatment of waste electronic products mainly involve two fields of renewable resources and environmental protection. A relatively perfect management system has been formed for green design and the manufacturing, recycling, treatment, remanufacturing, and disposal of the resources of electronic products, with strict reference standards. Therefore, waste electronic products are easier to “record on the chain” than other products, and the process of “recording to the chain” will be more standardized and standard.

2、Electronic Products Supply Chain

Unlike other durable goods, electronic products tend to have a short life cycle, fast response time, high pollution, and high recycling value. With low recycling rates and a lack of government and consumer involvement ^[10], waste electronics have become one of the fastest growing waste streams in the world, with a significant impact on the earth’s environment. Therefore, the research on the recycling of waste electronics has high theoretical and practical value. Due to the above characteristics of electronic products, Yang et al. ^[11] argued that electronics will face the risk of rapidly increasing technological innovation, which will lead to a significant decrease in parts cost, sales price, and demand. Tansel ^[12] also pointed out the challenges associated with the increase in the amount of waste electronics. Wang et al. ^[13] studied how high-tech electronics companies can coordinate environmental protection and social responsibility while gaining profits in order to promote the sustainable development of the electronics supply chain in response to the problems of the rapid replacement of electronic products and high obsolescence rates, considering that precious metals in waste electronics can bring huge economic benefits to the recycling industry. Kumar et al. ^[14] highlighted the importance and benefits of recycling waste electronics and emphasized the importance of recycling facilities. Wang et al. ^[15] pointed out that the recycling of waste electronics has become a key bottleneck for the proper disposal of waste electronics for reuse and recycling and analyzed the barriers to waste electronics enterprises by various stakeholders in China. They showed that it is important for the government to provide some subsidies, tax breaks, and other support to formal recycling enterprises. Zlamparet et al. ^[16] confirmed various views on the feasibility of remanufacturing in the waste electronics industry and showed that the potential for buyback can be increased by implementing good management, eco-design, and the reuse of waste electronics, thus avoiding major barriers such as environmental concerns and consumer acceptance. In summary, research on the recycling of waste electronic products is crucial due to their rapid renewal, high pollution, and high recycling value attributes. Moreover, electronic products such as high demand products and the platform adhere to “no time, no space” restrictions on the sales characteristics, so most of the electronic products will be sold on the platform. WResearchers expand on the advantages of platform sales and further consider the platform as a recycler to explore the issue of recycling model options for waste electronics.

3、Selection of Recycling Model for Waste Products

In recent years, with the proposal of sustainable development, many the manufacturer save costs by recycling and remanufacturing activities. At present, there are many litera- tures on the analysis of the reverse recycling of waste products, and some results have been achieved on the issue of reverse recycling model selection. Around this theme, scholars have considered factors affecting the choice of recycling model, such as competition in recycling channels, the costs and benefits of remanufacturing, and the adoption of new recycling technology (platform). In terms of considering recycling channel competition. Savaskan et al. ^[17] explored the issue of recycling channel selection for waste products and found that retailers recycled at a higher rate than the manufacturer and third parties when other conditions are the same. Wu and Zhou ^[18] extended the model of Savaskan et al. (2004) to examine the influence of supply chain competition on the manufacturer’s choice of optimal recycling channels. The results showed that the manufacturer adopted a manufacturer-managed recycling strategy. Liu et al. ^[19] showed that the dual manufacturer-retailer recycling model is the best recycling choice model for the manufacturer, regardless of the intensity of competition. Huang et al. ^[20] showed that, in the forward supply chain, the manufacturers sell products through retailers, while, in the reverse supply chain, retailers compete with third parties to recycle waste products. The results showed that a single recycling channel model for retailers is always better than the third party model. In terms of considering the costs and benefits of remanufacturing. Hong et al. ^[21] considered the effect of advertising on consumers’ acceptance of re-products and compared the performance of a closed-loop supply chain under the mode of manufacturer, retailer, and third party recycling. He et al. ^[22] showed that retailers’ participation in recycling competition leads to an increase in the manufacturers’ remanufacturing costs, which is not conducive to improving recycling efficiency. In considering new recycling technology (platform). Wang et al. ^[23] pointed out that platforms can increase consumers’ willingness to recycle online by publishing green information such as environmental knowledge about product recycling and corporate social responsibility online. Liu and Huang [^[24] 24 ] considered the option of e-commerce platform recycling in the reverse recycling process and showed that the best strategy for the manufacturer and the platform is a separate recycling model for e-commerce platforms when the recycling price sensitivity is low. Most of the above studies are related to the offline recycling of waste products, and the recycling channels are mainly focused on the manufacturer, retailers, third parties, or online platforms for recycling; however, there are relatively few studies on recycling by the manufacturer with the help of online platforms. Particularly in the recycling of waste electronics, there is little research that considers both platform sales and recycling functions. This paperntry studies the selection of the recycling model of waste electronic products empowered by blockchain in a closed-loop supply chain on the basis of platform resale. This studentry aims to fill the gap of such research.

4、Application of Blockchain Technology in Supply Chain

Blockchain is a unique information technology with decentralized structure, dis- tributed storage mechanism, consensus algorithm, smart contract, asymmetric encryption, and other functions. It has the“4T” “4T” technology features of traceability, transparency, trust, and transaction, ensuring the security and transparency of network information ^[28]. Although the development and application of blockchain technology is still in its infancy, it has been accepted by more and more groups and organizations in recent years, and its application potential has been recognized by more and more industries. WResearchers review the relevant literature on the application of blockchain technology in the supply chain in recent years and analyze and summarize the benefits and challenges brought by the application of blockchain technology in the supply chain combined with the technical characteristics of blockchain. Babich and Hilary ^[29] summarized five key advantages and five major weaknesses of blockchain technology in operations management. They also pointed out that blockchain technology improves supply chain operations through its advantages of transparency, information aggregation, information verification, automation, and system resilience, thereby creating a more stable, secure, efficient, ethical, and robust supply chain system. Lim et al. ^[30] pointed out that blockchain enables supply chain information sharing, maintains traceability throughout the process, and improves the efficiency of supply chain operations. Moreover, blockchain technology will bring disruptive changes to supply chain operations. Wang et al. ^[7] stated that blockchain overcomes the barriers of distrust, privacy issues, data misuse, and information asymmetry in information sharing between upstream and downstream of the supply chain by creating a transparent, trustworthy, and fair mechanism for sharing supply chain information. With the transparent and trustworthy nature of blockchain technology, Yu et al. ^[31] showed that small- and medium-sized enterprises (SMEs) can use self-guarantees to obtain loans from financial institutions and showed that platform guarantees with the help of blockchain are more efficient and market-effective compared to traditional platform guarantees. Shen et al. ^[32] categorized consumers into professional and novice types and explored the market conditions for brands and manufacturers to effectively combat counterfeit products by using blockchain technology. Cai and Choi ^[33] analyzed a supply chain model with the presence of a platform and found that the presence of a platform leads to a “triple marginal effect”, particularly that labeling con- tracts can coordinate the supply chain but may lead to moral hazard problems for retailers. The introduction of blockchain can effectively avoid moral hazard while coordinating the supply chain. Chod et al. ^[34] investigated the problem of asymmetric information from lenders to borrowers, specifically their operational capabilities, and studied the impact of two types of information reflecting borrowers’ operational capabilities: lenders’ application information and blockchain-recorded inventory transaction information on financing. The study  found that transparent inventory transaction information will produce less distortion in business financing. With the traceable characteristics of blockchain technology, Hastig and Sodhi ^[35] addressed the need for traceability systems in cobalt mining and pharmaceuticals industries, and presented the industry needs and critical success factors for blockchain implementation, laying the foundation for blockchain applications in the supply chain. Wu et al. ^[36] investigated the optimal strategy for different member-led blockchain construction in a fresh produce supply chain consisting of suppliers, third-party logistics service providers, and e-retailers, aiming at issues such as perishability and difficulty in the traceability of fresh produce. The study found that blockchain implementation was related to the consumer acceptance of products without blockchain technology, product spoilage rate, and the proportion of traceability costs borne by members when adopting blockchain. Liu et al. ^[37] proposed a five-layer smart traceability platform based on blockchain and the Internet of Things (IoT) to provide drug traceability and visibility solutions for the drug supply chain in response to the inability of pharmaceutical companies to address potential data manipulation and conflicts of interest by using traditional traceability platforms for controlling drug quality and improving transparency. In summary, the application of blockchain in supply chain management mainly focuses on the forward sales process of products, mostly relying on the trust, traceability, visibility, and other characteristics of blockchain technology, focusing on the research of product traceability and anti-counterfeiting. The theoretical research results of blockchain in the reverse recycling of waste products are rarely reported, especially in the electronics industry. This paperntry mainly relies on the transparency and traceability of blockchain technology to strengthen the supervision of the reverse recycling process and promote the real and effective recycling of waste electronic products in the closed-loop supply chain. In order to sort out the studies related to this paperntry and highlight the contributions of this paperentry, some representative articles are listed, compared, and analyzed in Table 1 Table 1, as follows.